Re: [CentOS] HP ProLiant DL380 G5
On 8/21/2014 9:50 PM, Keith Keller wrote: On 2014-08-22, Valeri Galtsevgalt...@kicp.uchicago.edu wrote: 3ware was independent company till it was first bought by AMCC, then LSI bought them from AMCC. I didn't know LSI sold them to someone else, Sorry, I was not clear: LSI was bought, not just 3ware. If you look at LSI's home page, it says An Avago Technologies Company. there's been a whole lot of merging and splitting. Avago used to be HP's semiconductor business, was spun off in the great split/merger with Compaq as part of Aglient, then in 2005 kicked to the curb as an independent. They are big on analog, mixed signal, and microwave semiconductors. LSI had acquired 3Ware, ONStor, a bunch more, and merged them into Engenio, which was their NAS/SAN division, making OEM storage arrays sold by IBM, HP, Dell and others. Engenio has been sold to Network Appliance, the original NAS company. LSI acquired the Sandforce SSD chip business. Avago acquired and merged with LSI. Avago unbundled Sandforce and sold it to Seagate. Avago sold LSI's networking stuff to Intel just last week. AFAIK, Avago still sells the LSI sas chips and both megaraid and 3ware raid controllers. -- john r pierce 37N 122W somewhere on the middle of the left coast ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] HP ProLiant DL380 G5
On 2014-08-22, John R Pierce pie...@hogranch.com wrote: there's been a whole lot of merging and splitting. You know more about this than is probably healthy. ;-) --keith -- kkel...@wombat.san-francisco.ca.us ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] HP ProLiant DL380 G5
On Thu, Aug 21, 2014 at 6:17 PM, John R Pierce pie...@hogranch.com wrote: Yes, but try a software RAID when you have intermittently bad RAM. I've been there. Mirrored disks that were almost, but not quite, mirrors. try any file system when you've got flakey ram.data thats not quite what you wanted, oh boy. Yes, but if you fix the RAM, fsck the disk, and rewrite the data you sort of expect it to work again. In this case with the mirrors randomly mismatching but marked as good, fsck would read the good one in some spots when checking but later the system would read the bad one. In hindsight the reason is obvious but it took me a while to see why the box still crashed every few weeks. which, btw, is why I insist on ECC for servers. and really prefer ZFS where each block of each part of a raid is checksummed and timestamped, so when scrub finds mismatching blocks, it can know which one is correct. I thought this was supposed to be ECC with 1-bit correction - and I thought that was supposed to mean that if it couldn't correct it would just stop, but it didn't. It took about 3 days of a memtest-86 run to hit the problem and show that it was RAM - and it has run for many subsequent years since swapping it all. But, the only reason that box is still around is that it is an enormous tower case and the only thing I had with enough drive bays for what I was doing then. -- Les Mikesell lesmikes...@gmail.com ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] HP ProLiant DL380 G5
Les Mikesell wrote: On Thu, Aug 21, 2014 at 6:17 PM, John R Pierce pie...@hogranch.com wrote: Yes, but try a software RAID when you have intermittently bad RAM. I've been there. Mirrored disks that were almost, but not quite, mirrors. try any file system when you've got flakey ram.data thats not quite what you wanted, oh boy. Yes, but if you fix the RAM, fsck the disk, and rewrite the data you sort of expect it to work again. In this case with the mirrors randomly mismatching but marked as good, fsck would read the good one in some spots when checking but later the system would read the bad one. In hindsight the reason is obvious but it took me a while to see why the box still crashed every few weeks. which, btw, is why I insist on ECC for servers. and really prefer ZFS where each block of each part of a raid is checksummed and timestamped, so when scrub finds mismatching blocks, it can know which one is correct. I thought this was supposed to be ECC with 1-bit correction - and I snip But wait, Jim, it's worse than that... does the 380 have *mirrored* memory? I know that the 580 I have does mark ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
[CentOS] HP ProLiant DL380 G5
I have CentOS 6.x installed on a HP ProLiant DL380 G5 server. It has eight 750GB drives in a hardware RAID6 array. Its acting as a host for a number of OpenVZ containers. Seems like every time I reboot this server which is not very often it sits for hours running a disk check or something on boot. The server is located 200+ miles away so its not very convenient to look at. Is there anyway to tell if it plans to run this or tell it not too? Right now its reporting one of the drives in array is bad and last time it did this a reboot resolved it. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] HP ProLiant DL380 G5
On 8/21/2014 12:43 PM, Matt wrote: I have CentOS 6.x installed on a HP ProLiant DL380 G5 server. It has eight 750GB drives in a hardware RAID6 array. Its acting as a host for a number of OpenVZ containers. Seems like every time I reboot this server which is not very often it sits for hours running a disk check or something on boot. The server is located 200+ miles away so its not very convenient to look at. Is there anyway to tell if it plans to run this or tell it not too? Right now its reporting one of the drives in array is bad and last time it did this a reboot resolved it. assuming thats a hp smartarray raid controller, use hpacucli to diagnose the raid problem. degraded raid6 is /really/ slow. -- john r pierce 37N 122W somewhere on the middle of the left coast ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] HP ProLiant DL380 G5
Matt wrote: I have CentOS 6.x installed on a HP ProLiant DL380 G5 server. It has eight 750GB drives in a hardware RAID6 array. Its acting as a host for a number of OpenVZ containers. Seems like every time I reboot this server which is not very often it sits for hours running a disk check or something on boot. The server is located 200+ miles away so its not very convenient to look at. Is there anyway to tell if it plans to run this or tell it not too? Right now its reporting one of the drives in array is bad and last time it did this a reboot resolved it. You need to know what it's running. If it's doing an fsck, that will take a lot of time. If it's firmware in the RAID controller, that's different. You can run tune2fs /dev/whatever and see how often it wants to run fsck. For that matter, what's the entry in /etc/fstab? mark ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] HP ProLiant DL380 G5
Hate to change the conversation here but that's why I hate hardware RAID. If it was software RAID, Linux would always tell you what's going on. Besides, Linux knows much more about what is going on on the disk and what is about to happen (like a megabyte DMA transfer). BTW, check if something is creating: /forcefsck That would make the fsck run every time. GKH Matt wrote: I have CentOS 6.x installed on a HP ProLiant DL380 G5 server. It has eight 750GB drives in a hardware RAID6 array. Its acting as a host for a number of OpenVZ containers. Seems like every time I reboot this server which is not very often it sits for hours running a disk check or something on boot. The server is located 200+ miles away so its not very convenient to look at. Is there anyway to tell if it plans to run this or tell it not too? Right now its reporting one of the drives in array is bad and last time it did this a reboot resolved it. You need to know what it's running. If it's doing an fsck, that will take a lot of time. If it's firmware in the RAID controller, that's different. You can run tune2fs /dev/whatever and see how often it wants to run fsck. For that matter, what's the entry in /etc/fstab? mark ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] HP ProLiant DL380 G5
You know that hpacucli (and MegaCli on LSI-based hardware RAID systems) can usually tell you more about the array and the drives than mdadm can, right? Also, if you're doing parity, having hardware RAID moves the parity calculations to a dedicated ASIC, avoiding any load of note on the CPU. Also, with hardware RAID, you get battery-backed or flash-backed write-back caching, which can dramatically improve performance. That said, mdadm is better that cheap fake-RAID controllers like you find on most mainboards, I will give you that. digimer On 21/08/14 04:33 PM, GKH wrote: Hate to change the conversation here but that's why I hate hardware RAID. If it was software RAID, Linux would always tell you what's going on. Besides, Linux knows much more about what is going on on the disk and what is about to happen (like a megabyte DMA transfer). BTW, check if something is creating: /forcefsck That would make the fsck run every time. GKH Matt wrote: I have CentOS 6.x installed on a HP ProLiant DL380 G5 server. It has eight 750GB drives in a hardware RAID6 array. Its acting as a host for a number of OpenVZ containers. Seems like every time I reboot this server which is not very often it sits for hours running a disk check or something on boot. The server is located 200+ miles away so its not very convenient to look at. Is there anyway to tell if it plans to run this or tell it not too? Right now its reporting one of the drives in array is bad and last time it did this a reboot resolved it. You need to know what it's running. If it's doing an fsck, that will take a lot of time. If it's firmware in the RAID controller, that's different. You can run tune2fs /dev/whatever and see how often it wants to run fsck. For that matter, what's the entry in /etc/fstab? mark ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos -- Digimer Papers and Projects: https://alteeve.ca/w/ What if the cure for cancer is trapped in the mind of a person without access to education? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] HP ProLiant DL380 G5
Hate to change the conversation here but that's why I hate hardware RAID. If it was software RAID, Linux would always tell you what's going on. Besides, Linux knows much more about what is going on on the disk and what is about to happen (like a megabyte DMA transfer). BTW, check if something is creating: /forcefsck These exist: -rw-r--r--1 root root 0 Jul 7 10:03 .autofsck -rw-r--r--1 root root 0 Jul 7 10:03 .autorelabel What does that mean? That would make the fsck run every time. GKH Matt wrote: I have CentOS 6.x installed on a HP ProLiant DL380 G5 server. It has eight 750GB drives in a hardware RAID6 array. Its acting as a host for a number of OpenVZ containers. Seems like every time I reboot this server which is not very often it sits for hours running a disk check or something on boot. The server is located 200+ miles away so its not very convenient to look at. Is there anyway to tell if it plans to run this or tell it not too? Right now its reporting one of the drives in array is bad and last time it did this a reboot resolved it. You need to know what it's running. If it's doing an fsck, that will take a lot of time. If it's firmware in the RAID controller, that's different. You can run tune2fs /dev/whatever and see how often it wants to run fsck. For that matter, what's the entry in /etc/fstab? mark ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] HP ProLiant DL380 G5
Matt wrote: Hate to change the conversation here but that's why I hate hardware RAID. If it was software RAID, Linux would always tell you what's going on. Besides, Linux knows much more about what is going on on the disk and what is about to happen (like a megabyte DMA transfer). BTW, check if something is creating: /forcefsck These exist: -rw-r--r--1 root root 0 Jul 7 10:03 .autofsck -rw-r--r--1 root root 0 Jul 7 10:03 .autorelabel What does that mean? ARRRGGGHGHGHGHGHGHHGHG!!! First, delete /.autofsck. That will stop it from fsckin'g *everything* every reboot. Second, is selinux in enforcing mode? In any case, have you recently done major changes? If not, delete /.autorelabel, since an selinux relabel takes a *while*, esp. if you have *lots* of files. mark ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] HP ProLiant DL380 G5
Am 21.08.2014 um 23:00 schrieb m.r...@5-cent.us: Matt wrote: Hate to change the conversation here but that's why I hate hardware RAID. If it was software RAID, Linux would always tell you what's going on. Besides, Linux knows much more about what is going on on the disk and what is about to happen (like a megabyte DMA transfer). BTW, check if something is creating: /forcefsck These exist: -rw-r--r--1 root root 0 Jul 7 10:03 .autofsck -rw-r--r--1 root root 0 Jul 7 10:03 .autorelabel What does that mean? ARRRGGGHGHGHGHGHGHHGHG!!! First, delete /.autofsck. That will stop it from fsckin'g *everything* every reboot. Second, is selinux in enforcing mode? In any case, have you recently done major changes? If not, delete /.autorelabel, since an selinux relabel takes a *while*, esp. if you have *lots* of files. mark No, /.autofsck is not harmful and will cause nothing unless /etc/sysconfig/autofsck exists and has something specific defined. The /.autofsck is automatically created at each boot by the system. /.autorelabel is as well only a control file and does not cause a full SELiux relabeling at each boot. If you don't believe me, please see /etc/rc.sysinit. Alexander ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] HP ProLiant DL380 G5
Hate to change the conversation here but that's why I hate hardware RAID. If it was software RAID, Linux would always tell you what's going on. Besides, Linux knows much more about what is going on on the disk and what is about to happen (like a megabyte DMA transfer). BTW, check if something is creating: /forcefsck These exist: -rw-r--r--1 root root 0 Jul 7 10:03 .autofsck -rw-r--r--1 root root 0 Jul 7 10:03 .autorelabel What does that mean? ARRRGGGHGHGHGHGHGHHGHG!!! First, delete /.autofsck. That will stop it from fsckin'g *everything* every reboot. Second, is selinux in enforcing mode? In any case, have you recently done major changes? If not, delete /.autorelabel, since an selinux relabel takes a *while*, esp. if you have *lots* of files. mark The directions for installing OpenVZ on Centos 6 stated to disable selinux, on this box I missed that step, whoops. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] HP ProLiant DL380 G5
On Thu, August 21, 2014 3:54 pm, Matt wrote: Hate to change the conversation here but that's why I hate hardware RAID. I love hardware RAID. 3ware more than others. In case of hardware RAID it is tiny specialized system (firmware) that is doing RAID function. In the specialized CPU (I should have called it differently) inside hardware RAID controller. Independent on the rest of computer, and needing only power to keep going. Tiny piece of code, very simple function. It is really hard to introduce bugs into these. Therefore you unlikely will have problem on device level. To find the status of the device and its components (physical drives) you always can use utility that comes from hardware vendor, you can have even web interface if it is 3ware. If it was software RAID, Linux would always tell you what's going on. It does. And so does hardware RAID device. And most of them (3ware in particular) do not do offline (i.e. delaying boot) check/rebuild, but they do it online (they are being operational in degraded state, and do necessary rebuild with IO present on the device, they just export themselves to Linux kernel with the warning of being degraded RAID during boot). Software RAID, however, has a disadvantage (more knowledgeable people will correct me wherever necessary). Software RAID function is executed by main CPU. Under very sophisticated system (linux kernel), as one of the processes (even if it is real time process), on the system that is switching between processes. Therefore, RAID task for software RAID lives in much more dangerous environment. Now, if it never finishes (say, kernel panics due to something else), you get inconsistent device (software RAID one), and it is much much much harder task to bring that to to some extent consistent state than, e.g., to bring back dirty filesystem that lives on the sane device. This is why we still pay for hardware RAID devices. I do. Just my 2c. Valeri Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] HP ProLiant DL380 G5
Hate to change the conversation here but that's why I hate hardware RAID. If it was software RAID, Linux would always tell you what's going on. Besides, Linux knows much more about what is going on on the disk and what is about to happen (like a megabyte DMA transfer). BTW, check if something is creating: /forcefsck These exist: -rw-r--r--1 root root 0 Jul 7 10:03 .autofsck -rw-r--r--1 root root 0 Jul 7 10:03 .autorelabel What does that mean? ARRRGGGHGHGHGHGHGHHGHG!!! First, delete /.autofsck. That will stop it from fsckin'g *everything* every reboot. Second, is selinux in enforcing mode? In any case, have you recently done major changes? If not, delete /.autorelabel, since an selinux relabel takes a *while*, esp. if you have *lots* of files. mark No, /.autofsck is not harmful and will cause nothing unless /etc/sysconfig/autofsck exists and has something specific defined. The /.autofsck is automatically created at each boot by the system. /.autorelabel is as well only a control file and does not cause a full SELiux relabeling at each boot. If you don't believe me, please see /etc/rc.sysinit. Alexander So I just need to SELINUXTYPE=disabled and ignore .autofsck and .autorelabel? Was the targeted selinux causing the slow reboots? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] HP ProLiant DL380 G5
Have you inspected via the system iLO console? Assuming it's cabled to the network On 08/21/2014 01:33 PM, GKH wrote: Hate to change the conversation here but that's why I hate hardware RAID. If it was software RAID, Linux would always tell you what's going on. Besides, Linux knows much more about what is going on on the disk and what is about to happen (like a megabyte DMA transfer). BTW, check if something is creating: /forcefsck That would make the fsck run every time. GKH Matt wrote: I have CentOS 6.x installed on a HP ProLiant DL380 G5 server. It has eight 750GB drives in a hardware RAID6 array. Its acting as a host for a number of OpenVZ containers. Seems like every time I reboot this server which is not very often it sits for hours running a disk check or something on boot. The server is located 200+ miles away so its not very convenient to look at. Is there anyway to tell if it plans to run this or tell it not too? Right now its reporting one of the drives in array is bad and last time it did this a reboot resolved it. You need to know what it's running. If it's doing an fsck, that will take a lot of time. If it's firmware in the RAID controller, that's different. You can run tune2fs /dev/whatever and see how often it wants to run fsck. For that matter, what's the entry in /etc/fstab? mark ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] HP ProLiant DL380 G5
Valeri, I hope you realize that your arguments for hardware RAID all depend on everything working just right. If something goes wrong with a disk (on HW RAID) you can't just simply take out the disk, move it to another computer and maybe do some forensics. The formatting of disks on HW RAID is transparent to Linux. Therefore my disks are all RAID or not. What if I wanted to mix and match? Maybe I don't want my swap RAID for performance. The idea of taking my data (which is controlled by an OSS Operating System, Linux) and putting it behind a closed source and closed system RAID controller is appalling to me. It comes down to this: Linux knows where and when to position the heads of disks in order to max performance. If a RAID controller is in the middle, whatever algorithm Linux is using is no longer valid. The RAID controller is the one who makes the I/O decisions. Sorry, this is not something I want to live with. GKH On Thu, August 21, 2014 3:54 pm, Matt wrote: Hate to change the conversation here but that's why I hate hardware RAID. I love hardware RAID. 3ware more than others. In case of hardware RAID it is tiny specialized system (firmware) that is doing RAID function. In the specialized CPU (I should have called it differently) inside hardware RAID controller. Independent on the rest of computer, and needing only power to keep going. Tiny piece of code, very simple function. It is really hard to introduce bugs into these. Therefore you unlikely will have problem on device level. To find the status of the device and its components (physical drives) you always can use utility that comes from hardware vendor, you can have even web interface if it is 3ware. If it was software RAID, Linux would always tell you what's going on. It does. And so does hardware RAID device. And most of them (3ware in particular) do not do offline (i.e. delaying boot) check/rebuild, but they do it online (they are being operational in degraded state, and do necessary rebuild with IO present on the device, they just export themselves to Linux kernel with the warning of being degraded RAID during boot). Software RAID, however, has a disadvantage (more knowledgeable people will correct me wherever necessary). Software RAID function is executed by main CPU. Under very sophisticated system (linux kernel), as one of the processes (even if it is real time process), on the system that is switching between processes. Therefore, RAID task for software RAID lives in much more dangerous environment. Now, if it never finishes (say, kernel panics due to something else), you get inconsistent device (software RAID one), and it is much much much harder task to bring that to to some extent consistent state than, e.g., to bring back dirty filesystem that lives on the sane device. This is why we still pay for hardware RAID devices. I do. Just my 2c. Valeri Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] HP ProLiant DL380 G5
On Thu, Aug 21, 2014 at 5:32 PM, GKH x...@darksmile.net wrote: I hope you realize that your arguments for hardware RAID all depend on everything working just right. Yes, but try a software RAID when you have intermittently bad RAM. I've been there. Mirrored disks that were almost, but not quite, mirrors. If something goes wrong with a disk (on HW RAID) you can't just simply take out the disk, move it to another computer and maybe do some forensics. You can if that other computer has a matching controller. If you expect to do forensics you should have that. Most people would just use a backup, though. What if I wanted to mix and match? Maybe I don't want my swap RAID for performance. If you want performance, you'll have enough RAM that you won't ever page swap back in. The idea of taking my data (which is controlled by an OSS Operating System, Linux) and putting it behind a closed source and closed system RAID controller is appalling to me. Why? It should all be backed up. It comes down to this: Linux knows where and when to position the heads of disks in order to max performance. If a RAID controller is in the middle, whatever algorithm Linux is using is no longer valid. Really??? I don't think linux has ever known or cared much about disk geometry and most disks lie about it anyway. The RAID controller is the one who makes the I/O decisions. Sorry, this is not something I want to live with. I think you haven't actually measured any performance. -- Les Mikesell lesmikes...@gmail.com ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] HP ProLiant DL380 G5
On 8/21/2014 4:06 PM, Les Mikesell wrote: Yes, but try a software RAID when you have intermittently bad RAM. I've been there. Mirrored disks that were almost, but not quite, mirrors. try any file system when you've got flakey ram.data thats not quite what you wanted, oh boy. -- john r pierce 37N 122W somewhere on the middle of the left coast ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] HP ProLiant DL380 G5
On 8/21/2014 4:11 PM, John R Pierce wrote: On 8/21/2014 4:06 PM, Les Mikesell wrote: Yes, but try a software RAID when you have intermittently bad RAM. I've been there. Mirrored disks that were almost, but not quite, mirrors. try any file system when you've got flakey ram.data thats not quite what you wanted, oh boy. which, btw, is why I insist on ECC for servers. and really prefer ZFS where each block of each part of a raid is checksummed and timestamped, so when scrub finds mismatching blocks, it can know which one is correct. -- john r pierce 37N 122W somewhere on the middle of the left coast ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] HP ProLiant DL380 G5
On Thu, Aug 21, 2014 at 3:43 PM, Matt matt.mailingli...@gmail.com wrote: I have CentOS 6.x installed on a HP ProLiant DL380 G5 server. It has eight 750GB drives in a hardware RAID6 array. Its acting as a host for a number of OpenVZ containers. Seems like every time I reboot this server which is not very often it sits for hours running a disk check or something on boot. The server is located 200+ miles away so its not very convenient to look at. Is there anyway to tell if it plans to run this or tell it not too? Right now its reporting one of the drives in array is bad and last time it did this a reboot resolved it. run: tune2fs -l /dev/mapper/whatever_the_disk_is_called check: Maximum mount count Next check after if those are NOT -1 and 0 respectively change settings by running: tune2fs -i 0 -c 0 /dev/mapper/whatever_the_disk_is_called ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] HP ProLiant DL380 G5
On Thu, August 21, 2014 5:32 pm, GKH wrote: Valeri, I hope you realize that your arguments for hardware RAID all depend on everything working just right. If something goes wrong with a disk (on HW RAID) you can't just simply take out the disk, move it to another computer and maybe do some forensics. If the drive that is member of hardware RAID failed (say timed out while dealing with reallocation of badblock), it is kicked out of the RAID, I get notification by 3ware daemon, hot unplug the drive, hot plug in replacement (of same or larger size), and start rebuild RAID through firmware utility, or GUI interface, or controller starts RAID rebuild automatically if configured so. The system on the machine has no idea about all this and keeps running happily. I do no forensics on failed drives. I run manufacturer drive fitness test (whichever it is called by particular manufacturer), if drive passes, I usually reuse it, if it fails test, I send it to drive manufacturer for warranty replacement or toss if it is out of warranty. The formatting of disks on HW RAID is transparent to Linux. Therefore my disks are all RAID or not. What if I wanted to mix and match? With 3ware RAID controller you can export one or more of attached drives directly to the system. They can not participate in [hardware] RAID then. Maybe I don't want my swap RAID for performance. Speaking of swap: RAM is large and cheap these days. I do not use swap on machines with 32 GB of RAM or larger. On multitasking system you have to switch between processes, which is more often than every millisecond. Imagine now you need to swap in or out 32GB during some of the switching between processes. Your system will be on its knees just because of that. Unless you have very special block device which is almost as fast as RAM, which you better just have added to the address space of RAM (from kernel point of view), so we are not speaking of these devices as of hard drives. The idea of taking my data (which is controlled by an OSS Operating System, Linux) and putting it behind a closed source and closed system RAID controller is appalling to me. Me too. Yet all of us use them. Example: hard drive firmware. Which has a bit more sophisticated function than just take data and write track or other way around. It detects badblocks, reallocated them, recovers as much as possible information that was inside that bad block. Another example: video card, say, NVIDIA one. It has processors inside that run software that is flashed on its non-volatile memory. Now, with Nvidia cards sometimes you have to use proprietary driver (if you have more or less sophisticated display arrangement). Which is closed code binary driver. What you compile when you install that is just an interface between closed code driver and this particular version of kernel. And this code runs not in the card itself, but under your system. And the list goes on. Not to mention our cell phones... The only time I was mad about firmware of some controller was one particular version of via PATA controller that had a bug which was leading to drive corruption... It comes down to this: Linux knows where and when to position the heads of disks in order to max performance. If a RAID controller is in the middle, whatever algorithm Linux is using is no longer valid. The RAID controller is the one who makes the I/O decisions. Yes, but... And some of what I'll say was already mentioned in this thread. You can tweak RAID controller to align stripe sizes with optimal data chunks of the drives. Furthermore, you can have cache (battery backed up), which increases device speed tremendously (30 times I saw for something particular - just off the top of my head). Of course, RAM is used as a cache for software RAID, but to the contrary to RAID controller cache RAM content vanishes with power loss. You don't seem to be the person who had to recover after [software] RAID cache loss. And _I_ definitely will not like to be the one. Hence I use hardware RAID, with optimized stripe size, and optimized filesystem block size, and with cache in RAID controller that is battery backed up. If you beat me in IO with software RAID, I will live with that. As I do not like to give up reliability. Not at as small extra cost as I have to pay for hardware RAID. (And I do not include into hardware RAID these fake raid cards that rely on driver - which are indeed software RAID cards. 3ware never fell that low to make/sell any of such junk. Somebody who knows LSI better than I do will probably say the same about them). Again, just my 2c. Valeri Sorry, this is not something I want to live with. GKH On Thu, August 21, 2014 3:54 pm, Matt wrote: Hate to change the conversation here but that's why I hate hardware RAID. I love hardware RAID. 3ware more than others. In case of hardware RAID it is tiny specialized system (firmware) that is doing RAID function. In the specialized CPU (I should
Re: [CentOS] HP ProLiant DL380 G5
On 2014-08-21, Valeri Galtsev galt...@kicp.uchicago.edu wrote: (And I do not include into hardware RAID these fake raid cards that rely on driver - which are indeed software RAID cards. 3ware never fell that low to make/sell any of such junk. Somebody who knows LSI better than I do will probably say the same about them). LSI has owned 3ware for some time (who in turn were recently gobbled by some other company). The LSI MegaRAID cards are real hardware RAID. What I have heard, but only validated the former, is that the 3ware UI is simpler but the MegaRAID controllers are faster. That being said, I do also like mdraid for certain purposes. I was able to successfully repurpose a very old controller in an old but nicely sized chassis (16 bays) by moving to an md RAID6 array, which the hardware controller doesn't support (I did say it's old). I also love the want_replacement feature in md RAID, a feature I don't believe is supported in the 3ware line (you can rebuild just one disk if it's bad but hasn't been kicked out of the array yet; that rebuild is much faster). --keith -- kkel...@wombat.san-francisco.ca.us ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] HP ProLiant DL380 G5
On Thu, August 21, 2014 6:47 pm, Keith Keller wrote: On 2014-08-21, Valeri Galtsev galt...@kicp.uchicago.edu wrote: (And I do not include into hardware RAID these fake raid cards that rely on driver - which are indeed software RAID cards. 3ware never fell that low to make/sell any of such junk. Somebody who knows LSI better than I do will probably say the same about them). LSI has owned 3ware for some time (who in turn were recently gobbled by some other company). 3ware was independent company till it was first bought by AMCC, then LSI bought them from AMCC. I didn't know LSI sold them to someone else, www.3ware.com still redirects to LSI. To the credit of all 3ware owners, they left nicely working 3ware (engineering, manufacturing, etc) mechanism as is without destroying it. Which is rare, and they deserve my respect for that alone. I do like LSI too, and have a few of their megaraid controllers on long lived and still very reliable boxes. I do like 3ware more as as you said it has more transparent UI, which in my book diminishes chance of human error tremendously. And I'm merely human. I do like 3ware is coming with daemon that watches and notifies me when necessary. The LSI MegaRAID cards are real hardware RAID. I never heard about any LSI card called RAID which are not hardware RAID. I can not say the same about, say, Adaptec or HighPoint to name two. Some of Adaptec and some of HighPoint cards even though they are sold as RAID cards are junk and have no place in our server room. Areca, probably, is one more company whose RAID cards all are indeed hardware RAID cards (I have 3 or 4 Areca cards in our server room). So let me name them separately (I consider bad guys everybody who sells as RAID card at least one product which is not hardware RAID card, they confuse the world and interfere with fair profits of good guys): good guys: LSI, 3ware, Areca bad guys: Adaptec, HighPoint Somebody correct me if/where I'm wrong. Valeri What I have heard, but only validated the former, is that the 3ware UI is simpler but the MegaRAID controllers are faster. That being said, I do also like mdraid for certain purposes. I was able to successfully repurpose a very old controller in an old but nicely sized chassis (16 bays) by moving to an md RAID6 array, which the hardware controller doesn't support (I did say it's old). I also love the want_replacement feature in md RAID, a feature I don't believe is supported in the 3ware line (you can rebuild just one disk if it's bad but hasn't been kicked out of the array yet; that rebuild is much faster). --keith -- kkel...@wombat.san-francisco.ca.us ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] HP ProLiant DL380 G5
On 8/21/2014 5:49 PM, Valeri Galtsev wrote: I never heard about any LSI card called RAID which are not hardware RAID. the base LSI SAS HBA cards, like the 2008 chip (9211-8i etc boards) have microcoded hardware raid without any write buffer or battery backup Its not quite fake raid but its kinda in limbo.. I *much* prefer to use these cards in IT mode, which requires reflashing the firmware and BIOS, as they always seem to be shipped in IR mode. IT mode is plain SAS2 Initiator-Target mode, where the disks are just plain disks without needing to create volumes or any other nonsense. -- john r pierce 37N 122W somewhere on the middle of the left coast ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] HP ProLiant DL380 G5
On 2014-08-22, Valeri Galtsev galt...@kicp.uchicago.edu wrote: 3ware was independent company till it was first bought by AMCC, then LSI bought them from AMCC. I didn't know LSI sold them to someone else, Sorry, I was not clear: LSI was bought, not just 3ware. If you look at LSI's home page, it says An Avago Technologies Company. --keith -- kkel...@wombat.san-francisco.ca.us ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
