RE: First RAID Setup
You should have a designated spare for RAID-5. Not sure why you have 3 disks for each RAID1, RAID1 is mirror, and unless the third drive is a spare, it is not needed. Thanks, Tom Callahan -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Andargor The Wise Sent: Thursday, December 15, 2005 2:10 PM To: linux-raid@vger.kernel.org Subject: First RAID Setup I admit it. I'm a RAID virgin. However, after a disastrous failure of the sole drive I wasn't backing up, I decided to go RAID-5 under Slack 10.2 (first time ever with RAID-5). The config: Asus P5GL-MX (ICH6) mobo w/1 GB RAM, 4 x SATA ports P4 3.0G/1M 3 x WD2000JS 200.0 GB SATA drives First, a question: the BIOS on this machine seems to list the SATA ports as third/fourth IDE master/slave. Further, the documentation seems to say that SATA 1/2 are master and SATA 3/4 are slave (black and red connectors, respectively). My understanding is that SATA drives are each on separate buses. Is this because the BIOS offers a P-ATA emulation mode for SATA and it makes it easier to understand for novices to show them that way? I ask because people have said that it is not a good idea to have both IDE masters and slaves on the same bus as part of a RAID-5 array. I know SATA is different, but will using three of the SATA ports on this mobo be OK? Second, after reading the excellent advice in this list, I decided that booting from RAID-5 might not be a good idea. So this is what I've been thinking: Each disk partitioned alike: 1 30MB 2 8GB (to allow for memory upgrades later) 5 rest_of_disk mds: md0 raid1 sda1 sdb1 sdc1 md1 raid1 sda2 sdb2 sdc2 md2 raid5 sda5 sdb5 sdc5 md0 /boot md1 swap md2 / Does this look OK? What should the stripe and chunk sizes be, considering I'll be going with reiserfs? Typical usage: development machine, some DB apps with medium load, read-only mostly, not many writes. Very few large files (such as multimedia). Or should I set up separate RAID-5's for /usr and /var as well? Lastly, can I install directly to this configuration, or should I install on a separate disk and move things into the array? Andargor __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com - To unsubscribe from this list: send the line unsubscribe linux-raid in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html - To unsubscribe from this list: send the line unsubscribe linux-raid in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
RE: First RAID Setup
I understand the reason for the RAID1 devices. I was asking why you have 3 devices in the RAID1 setup? RAID1 is a mirrored configuration, requiring only 2 disks for operation. It is always wise to build in a spare however, that being said about all raid levels. In your configuration, if a disk fails in your RAID5, your array will go down. RAID5 is usually 3+ disks, with a mirror. So you should have 3 disks at minimum, and then a 4th as a spare. The MD modules/subsystem will then automagically bring in that spare disk if any of the existing 3 in your RAID5 setup fail. It is wise to think through your layout prior to building, and I commend you for that. You may also want to review/experiment with the MD subsystem. For instance, There is a neat --grow mode that is not mentioned in many vendor man pages that can allow you to grow an MD device as needed. Another gotcha, it's usually better to use entire disks, if you can afford to, in an MD array. This alleviates growing pains of having to manually repartition if you want to grow an exisiting filesystem. This may not make much sense now, but once you have to do it, you'll smack your forehead in grief. Thanks, Tom Callahan -Original Message- From: Andargor The Wise [mailto:[EMAIL PROTECTED] Sent: Thursday, December 15, 2005 2:45 PM To: Callahan, Tom; linux-raid@vger.kernel.org Subject: RE: First RAID Setup The RAID1 partitions are to make sure: 1) The machine is able to boot even if a disk is lost (/boot). 2) The machine isn't brought down if a disk is lost (swap) I thought about a spare drive, but I don't need high availability. I'm satisfied with being able to recover my data. Andargor --- Callahan, Tom [EMAIL PROTECTED] wrote: You should have a designated spare for RAID-5. Not sure why you have 3 disks for each RAID1, RAID1 is mirror, and unless the third drive is a spare, it is not needed. Thanks, Tom Callahan -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Andargor The Wise Sent: Thursday, December 15, 2005 2:10 PM To: linux-raid@vger.kernel.org Subject: First RAID Setup I admit it. I'm a RAID virgin. However, after a disastrous failure of the sole drive I wasn't backing up, I decided to go RAID-5 under Slack 10.2 (first time ever with RAID-5). The config: Asus P5GL-MX (ICH6) mobo w/1 GB RAM, 4 x SATA ports P4 3.0G/1M 3 x WD2000JS 200.0 GB SATA drives First, a question: the BIOS on this machine seems to list the SATA ports as third/fourth IDE master/slave. Further, the documentation seems to say that SATA 1/2 are master and SATA 3/4 are slave (black and red connectors, respectively). My understanding is that SATA drives are each on separate buses. Is this because the BIOS offers a P-ATA emulation mode for SATA and it makes it easier to understand for novices to show them that way? I ask because people have said that it is not a good idea to have both IDE masters and slaves on the same bus as part of a RAID-5 array. I know SATA is different, but will using three of the SATA ports on this mobo be OK? Second, after reading the excellent advice in this list, I decided that booting from RAID-5 might not be a good idea. So this is what I've been thinking: Each disk partitioned alike: 1 30MB 2 8GB (to allow for memory upgrades later) 5 rest_of_disk mds: md0 raid1 sda1 sdb1 sdc1 md1 raid1 sda2 sdb2 sdc2 md2 raid5 sda5 sdb5 sdc5 md0 /boot md1 swap md2 / Does this look OK? What should the stripe and chunk sizes be, considering I'll be going with reiserfs? Typical usage: development machine, some DB apps with medium load, read-only mostly, not many writes. Very few large files (such as multimedia). Or should I set up separate RAID-5's for /usr and /var as well? Lastly, can I install directly to this configuration, or should I install on a separate disk and move things into the array? Andargor __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com - To unsubscribe from this list: send the line unsubscribe linux-raid in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com - To unsubscribe from this list: send the line unsubscribe linux-raid in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
RE: resize2fs failing--how to resize my fs?
Was this resize done while the FS was mounted? Thanks, Tom Callahan -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Michael Stumpf Sent: Wednesday, December 14, 2005 3:33 PM To: linux-raid@vger.kernel.org Subject: Re: resize2fs failing--how to resize my fs? Michael Stumpf wrote: I get this from the latest stable resize2fs: [EMAIL PROTECTED] parted]# resize2fs /dev/my_vol_grp/my_log_vol resize2fs 1.38 (30-Jun-2005) Resizing the filesystem on /dev/my_vol_grp/my_log_vol to 488390656 (4k) blocks. Killed Parted (again, latest stable) tells me the following: Using /dev/mapper/my_vol_grp-my_log_vol (parted) resize 1 0 100% No Implementation: This ext2 file system has a rather strange layout! Parted can't resize this (yet). (parted) Similar results from ext2resize/ext2online. This is an ordinary ext3 fs, living inside an LVM2 that has already been increased to accomodate (used all free extents).. I've resized it down and up before, though it is possible I am resizing it larger than it has been before (1.8TB). Not sure what's up. Any advice welcome; my research in this has me getting a bit nervous about lvm2 bugs causing loss of data. While I want a single resilient (via raid 5) volume, I may be willing to ditch a whole layer of software (lvm2) to get some security. Surprised noone has hit this before. It turns out that somehow my swap space disappeared in a system migration. This became more obvious as I explicitly tried to extend the fs to a lower limit (438390656), where resize2fs worked for a while, then informed me that it couldn't allocate some memory. Add 512mb of swap and problem solved.. never used more than ~100mb of swap (256mb main memory). Hope this helps someone. - To unsubscribe from this list: send the line unsubscribe linux-raid in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html - To unsubscribe from this list: send the line unsubscribe linux-raid in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
RE: s/w raid and bios renumbering HDs
You are testing failover with reboots. So when Linux probes the disks, it is putting hdc where hda used to be This seems a bit strange, as hda/hdb should theoretically be IDE1 and hdc/hdd should be IDE2 As far as your grub setup, it looks perfectly fine. You should have two entries as you have, because if disc1 fails, you cannot boot to hd(0,0) and vice-versa. One gotcha, make sure grub is installed in the MBR of BOTH drives, not just the MD device Thanks, Tom Callahan TESSCO Technologies Inc. 410-229-1361 -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Hari Bhaskaran Sent: Monday, October 31, 2005 10:57 AM To: linux-raid@vger.kernel.org Subject: s/w raid and bios renumbering HDs Hi, I am trying to setup a RAID-1 setup for the boot/root partition. I got the setup working, except what I see with some of my tests leave me less convinced that it is actually working. My system is debian 3.1 and I am not using the raid-setup options in the debian-installer, I am trying to add raid-1 to an existing system (followed http://www.tldp.org/HOWTO/Software-RAID-HOWTO.html -- 7.4 method 2) I have /dev/hda (master on primary) and /dev/hdc (master on secondary) setup as mirrors. I also have a cdrom on /dev/hdd. Now if I disconnect hda and reboot, everything seems work - except what used to be /dev/hdc comes up as /dev/hda. I know this since I the bios does complain that primary disk 0 is missing and I would have expected a missing hda, not a missing hdc. Anyways, the software seems to recognize the failed-disk fine if I connect the real hda back. Is this the way it is supposed to work? Can I rely on this? Also what happens when I move on to fancier setups like raid5?. My box is a dell 400sc with some phoenix bios (doesnt have many options either). I get different (still unexpected) results with the cdrom connected and not. Question #2 (probably related to my problem) My grub menu.lst is as follows (/dev/md0 is made of /dev/hda1 and /dev/hdc1) For testing, I made two entries (one for (hd0,0) and another for (hd1,0)). The howto I was reading wasn't clear to me. Should I be making just one entry pointing to /dev/md0? Also trying labels for hda and hdc after connecting the faulty drive back gave me different results ( in one case I was looking at older data and in the other case I wasn't) (ignore the vs2.1.xxx. it is a linux-vserver patch - shouldn't matter here) title Debian GNU/Linux, kernel 2.6.13.3-vs2.1.0-rc4-RAID-hda root(hd0,0) kernel /boot/vmlinuz-2.6.13.3-vs2.1.0-rc4 root=/dev/md0 ro initrd /boot/initrd.img-2.6.13.3-vs2.1.0-rc4.md0 savedefault boot title Debian GNU/Linux, kernel 2.6.13.3-vs2.1.0-rc4-RAID-hdc root(hd1,0) kernel /boot/vmlinuz-2.6.13.3-vs2.1.0-rc4 root=/dev/md0 ro initrd /boot/initrd.img-2.6.13.3-vs2.1.0-rc4.md0 savedefault boot Any help is appreciated. If there is a better/current HOWTO, please let me know. The ones I have seen so far refer to now deprecated tools (raidtools or raidtools2) and I have had a hard time trying to find the equivalent syntax for mdadm. -- Hari - To unsubscribe from this list: send the line unsubscribe linux-raid in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html - To unsubscribe from this list: send the line unsubscribe linux-raid in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
