Re: [linux-lvm] Installation question: SW RAID1 + LVM for boot and root
On Thu, Feb 08, 2001 at 09:39:49PM +0100, Luka Renko wrote: 1. Is it possible to install OS directly on SW RAID1 + LVM? If not, how to do it in multiple steps (RAID HOWTO just mentions how to install OS on SW RAID1, but not using LVM on top of SW RAID)? not yet, i used an extra disk to install the system on, then cpio-ed everything. 2. Are there any known problems on LVM over SW RAID1 (I have seen some bug reports on that)? no, if you use the 0.9.1betaX 3. RAID HOWTO talks about slow read performance with RAID1 and that it should be improved in new patches to come? Is this still true? Do I need to apply any patches for that? i believe the code in 2.4 is optimized (but you better look for mikka's patch and see if it applies to you, i use raid5 so i dinna check). 4. I have also seen some discussion about issues with putting swap on SW RAID? Is this still true? with 2.2 it is problematic and cannot be fixed, it has been fixed in 2.4 5. Should I create one or two (system, user) md devices? Is there any difference? What about multiple LVM VGs and PVs? It seems to me, that it does not make any real difference... 1 md device, 1 pv, 1 vg (no way out with only 2 disks) i dunno if the latest lilo can see LVM-OVER-RAID1, if not 1 small md device for /boot 1 big md for lvm 6. What version of kernel (2.2 or 2.4) is better for such configuration? What version of SW RAID and LVM should I use? Are there any additional patches I should apply? 2.4 (sw raid is included, lvm patches from cvs) -- Luca Berra -- [EMAIL PROTECTED] Communication Media Services S.r.l. /"\ \ / ASCII RIBBON CAMPAIGN XAGAINST HTML MAIL / \ - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to [EMAIL PROTECTED]
Re: RAID1 Read performance
In article [EMAIL PROTECTED] you wrote: Hello all, I have a 5G RAID1 device that I created under 2.2.16. The device is made of /dev/hda4 (Maxtor 102.G UDMA66) and /dev/hde4 (IBM 20.5G UDMA100). Under 2.2.16 'hdparm -t /dev/md0' gave read speeds of 22-26MB/sec on this combo. I've been running 2.4 series kernels for a while, and have noticed that access to the array takes a bit longer. 'hdparm -t /dev/md0' now tops out at 17MB/sec. Is this to be expected in the transition to 2.4, or did I mess something up? (single threaded) RAID1 performance in 2.4 is limited to the speed of the fastest disk[1]. Can you hdparm -t both your disks seperatly and post the numbers here ? Greetings, Arjan van de Ven [1] With a simple patch you can get it to the _sum_ of the throughput of the disks, but that requires an on-disk format change. - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to [EMAIL PROTECTED]
Re: RAID1 Read performance
On Fri, Feb 09, 2001 at 08:31:58AM -0800, Gregory Leblanc wrote: (single threaded) RAID1 performance in 2.4 is limited to the speed of the fastest disk[1]. Can you hdparm -t both your disks seperatly and post the numbers here ? I was under the impression that some form of the RAID 1 read balancing patch (for the 2.2.x kernels) had been incorporated into 2.4.x. Is this incorrect? With the current on-disk layout, it is not possible to exceed the speed of the fastest disk for single-threaded, sequential reads. The balancing patch works for either multi-threaded or non-sequential reads. Greetings, Arjan van de Ven - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to [EMAIL PROTECTED]
Re: RAID1 Read performance
(single threaded) RAID1 performance in 2.4 is limited to the speed of the fastest disk[1]. Can you hdparm -t both your disks seperatly and post the numbers here ? I was under the impression that some form of the RAID 1 read balancing patch (for the 2.2.x kernels) had been incorporated into 2.4.x. Is this incorrect? My individual drives clock in at: hda: 20-22MB/sec hde: 24-27MB/sec It certainly seems that there is no read balancing happening; does it make sense for no read balancing to translate to degraded read performance with respect to individual drives in the array? Ross Vandegrift [EMAIL PROTECTED] [EMAIL PROTECTED] - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to [EMAIL PROTECTED]
Status of raid.
Greetings, I'm getting ready to put kernel 2.4.1 on my server at home. I have some questions about the status of RAID in 2.4.1. Sorry to be dense but I couldn't glean the answers to these questions from my search of the mailing list. 1. It appears that as of 2.4.1 RAID is finally part of the standard kernel. Is this correct? 2. Which raidtools package do I use and where can I get it? Or is it, too, enclosed with the kernel? 3. Does the RAID in 2.4.1 have the read-balancing patch? -- / C. R. (Charles) Oldham | NCA Commission on Accreditation and \ / Director of Technology | School Improvement \ / [EMAIL PROTECTED] | V:480-965-8703 F:480-965-9423\ - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to [EMAIL PROTECTED]
Re: Status of raid.
On Friday February 9, [EMAIL PROTECTED] wrote: Greetings, I'm getting ready to put kernel 2.4.1 on my server at home. I have some questions about the status of RAID in 2.4.1. Sorry to be dense but I couldn't glean the answers to these questions from my search of the mailing list. 1. It appears that as of 2.4.1 RAID is finally part of the standard kernel. Is this correct? Yes, though you will need to wait for 2.4.2 if you want to compile md as a module. 2. Which raidtools package do I use and where can I get it? Or is it, too, enclosed with the kernel? The same ones you would use with patches 2.2. i.e. 0.90. 3. Does the RAID in 2.4.1 have the read-balancing patch? Yes, that patch is in. NeilBrown -- / C. R. (Charles) Oldham | NCA Commission on Accreditation and \ / Director of Technology | School Improvement \ / [EMAIL PROTECTED] | V:480-965-8703 F:480-965-9423\ - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to [EMAIL PROTECTED] - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to [EMAIL PROTECTED]
