Re: raid5 failure
On Fri, 21 Jul 2000, Seth Vidal wrote: Hi, We've been using the sw raid 5 support in linux for about 2-3 months now. We've had good luck with it. Until this week. In this one week we've lost two drives on a 3 drive array. Completely eliminating the array. We have good backups, made everynight, so the data is safe. The problem is this: What could have caused these dual drive failures? One went out on saturday the next on the following friday. Complete death. One drive won't detect anywhere anymore and its been RMA'd the other detects and I'm currently mke2fs -c on the drive. Hey Seth, Sorry to hear about your drive failures. To me, this is something that most people ignore about RAID5: Lose more than one drive and everything is toast. Good reason to have a drive setup as a hot spare, not to mention an extra drive laying on the shelf. And hold your breathe while the array is rebuilding. Bill Carlson Systems Programmer[EMAIL PROTECTED]| Opinions are mine, Virtual Hospital http://www.vh.org/| not my employer's. University of Iowa Hospitals and Clinics|
Re: Swap on RAID
On Thu, 1 Jun 2000, Henry J. Cobb wrote: Does anybody really want to wait while their swap data is duplicated out to multiple disks by a CPU that is working to free up memory to run applications? Isn't Swapping slow enough already? Why not simply swap on multiple disks, get Hardware RAID-5 for swap or buy RAM? Linux uses swap intelligently, if areas of memory don't change they get swapped out to disk, making more physical RAM available for file caching, etc. Having swap is good even if you have oodles of RAM just for that reason. Bill Carlson Systems Programmer[EMAIL PROTECTED]| Opinions are mine, Virtual Hospital http://www.vh.org/| not my employer's. University of Iowa Hospitals and Clinics|
Re: Raid5 with two failed disks?
On Thu, 30 Mar 2000, Martin Bene wrote: At 02:16 30.03.00, you wrote: Hi... I have a Raid5 Array, using 4 IDE HDs. A few days ago, the system hung, no reaction, except ping from the host, nothing to see on the monitor. I rebooted the system and it told me, 2 out of 4 disks were out of sync. 2 Disks have an event counter of 0062, the two others 0064. I hope, that there is a way to fix this. I searched through the mailing-list and found one thread, but it did not help me. Yes I do. Check Jakobs Raid howto, section "recovering from multiple failures". You can recreate the superblocks of the raid disks using mkraid; if you explicitly mark one disk as failed in the raidtab, no automatic resync is started, so you get to check if all works and perhaps change something and retry. Hey all, I've been thinking about this for a different project, how bad would it be to setup RAID 5 to allow for 2 (or more) failures in an array? Or is this handled under a different class of RAID (ignoring things like RAID 5 over mirrored disks and such). Three words: Net block device Bill Carlson Systems Programmer[EMAIL PROTECTED]| Opinions are mine, Virtual Hospital http://www.vh.org/| not my employer's. University of Iowa Hospitals and Clinics|
Re: Raid5 with two failed disks?
On Thu, 30 Mar 2000, Theo Van Dinter wrote: On Thu, Mar 30, 2000 at 08:36:52AM -0600, Bill Carlson wrote: I've been thinking about this for a different project, how bad would it be to setup RAID 5 to allow for 2 (or more) failures in an array? Or is this handled under a different class of RAID (ignoring things like RAID 5 over mirrored disks and such). You just can't do that with RAID5. I seem to remember that there's a RAID 6 or 7 that handles 2 disk failures (multiple parity devices or something like that.) You can optionally do RAID 5+1 where you mirror partitions and then stripe across them ala RAID 0+1. You'd have to lose 4 disks minimally before the array goes offline. 1+5 would still fail on 2 drives if those 2 drives where both from the same RAID 1 set. The wasted space becomes more than N/2, but it might worth it for the HA aspect. RAID 6 looks cleaner, but that would require someone to write an implementation, whereas you could do RAID 15 (51?) now. My thought here is leading to a distributed file system that is server independent, it seems something like that would solve a lot of problems that things like NFS and Coda don't handle. From what I've read GFS is supposed to do this, never hurts to attack a thing from a couple of directions. Use the net block device, RAID 15 and go. Very tempting...:) Bill Carlson Systems Programmer[EMAIL PROTECTED]| Opinions are mine, Virtual Hospital http://www.vh.org/| not my employer's. University of Iowa Hospitals and Clinics|
Re: Raid5 with two failed disks?
On Thu, 30 Mar 2000, Theo Van Dinter wrote: On Thu, Mar 30, 2000 at 02:21:45PM -0600, Bill Carlson wrote: 1+5 would still fail on 2 drives if those 2 drives where both from the same RAID 1 set. The wasted space becomes more than N/2, but it might worth it for the HA aspect. RAID 6 looks cleaner, but that would require someone to write an implementation, whereas you could do RAID 15 (51?) now. 2 drives failing in either RAID 1+5 or 5+1 results in a still available array: Doh, you're right. Thanks for drawing me a picture...:) Bill Carlson Systems Programmer[EMAIL PROTECTED]| Opinions are mine, Virtual Hospital http://www.vh.org/| not my employer's. University of Iowa Hospitals and Clinics|
Re: mkraid did not work !!
On Mon, 7 Feb 2000 [EMAIL PROTECTED] wrote: Hi ! I did install the raid like it is described at http://ostenfeld.dk/~jakob/Software-RAID.HOWTO/ with patch and latest raid-tools. After editing /etc/raidtab like sample with raid1 Hi Peter, Run dmesg and look for a line like 'autodetecting RAID arrays'. If it's not there, you're not running the patched code. Something like this would work: dmesg | grep -i raid to show you any raid output from boot. HTH, Bill Carlson Systems Programmer[EMAIL PROTECTED]| Opinions are mine, Virtual Hospital http://www.vh.org/| not my employer's. University of Iowa Hospitals and Clinics|
RE: Compaq smartSCSI doesn't recognise 2nd drive
On Tue, 1 Feb 2000, Newman Chakerian wrote: Thanks Bill for your comments I actually had the entries in fstab right when I tried it. (Sorry for the manual typos) I was wondering .. The Compaq Proliant has an internal SCSI Controller (NCRXX ??). The RedHat install picks this up no problem. AM I better off using the internal controller than the Smart SCSI 2, seeing as I don't want to use mirroring ? I read somewhere that the Smart SCSI 2 driver is not yet certified - It's a 'use at own risk' type of thing. I'm assuming that your SMART is one of the Hardware RAID controllers. Which to use is ultimately up to you and greatly depends on what you require for your data. If your data is very important, I'd run with the SMART, mirror and have a good backup plan. If speed is important, I'd run with the SMART and RAID 0. If stability is important, I might stick with the internal SCSI, I haven't run the SMART under linux that much. For most of my uses, I'd use both...:) Bill Carlson Systems Programmer[EMAIL PROTECTED]| Opinions are mine, Virtual Hospital http://www.vh.org/| not my employer's. University of Iowa Hospitals and Clinics|
Re: Compaq smartSCSI doesn't recognise 2nd drive
On Mon, 31 Jan 2000, Newman Chakerian wrote: here is my fstab file: the ones I'm trying to add are commented out (I added these entries myself): /dev/ida/c0d0p5 / ext2 defaults 1 1 /dev/ida/c0d0p1 /boot ext2 defaults 1 2 /dev/cdrom /mnt/cdrom iso9660 noauto,owner,ro 0 0 /dev/ida/c0d0p6 swapswap defaults 0 0 /dev/fd0/mnt/floppy ext2 noauto,owner 0 0 none/proc proc defaults 0 0 none/dev/ptsdevpts gid=5,mode=6200 0 #/dev/ida/c0d1p5 /optext2 default 1 3 #/dev/ida/c0d1/p1 /mnt/dsk2 ext2 defaults 1 1 I'm hoping this is a cut and paste of the file, you have typos in both lines. Also, make sure each entry is all one line. First entry: defaults instead of default Second entry: The device is incorrect, I think you want /dev/ida/c0d1p1 instead of /dev/ida/c0d1/p1. Might double check and make sure those partitions exist as well. HTH, Bill Carlson Systems Programmer[EMAIL PROTECTED]| Opinions are mine, Virtual Hospital http://www.vh.org/| not my employer's. University of Iowa Hospitals and Clinics|
RE: mkraid aborts, no info?
On Wed, 27 Oct 1999, Fernandez, Richard wrote: Mandrake doesn't have RAID support built into the kernel AFAIK. I was trying to do the same thing you're doing using Mandrake 6.0. Below is an e-mail I received from Mandrake... dear Richard Fernandez, you should recompile the kernel with raid support or use the RedHat compiled kernel which already has that. sincerely, -- Florin Grad (Technical Support Team) [EMAIL PROTECTED] I'm thinking Florin means the kernel is not compiled with support by default. From the info on raidtools: This package includes the tools you need to set up and maintain a software RAID device under Linux. It only works with Linux 2.2 kernels and later, or 2.0 kernel specifically patched with newer raid support. To me that implies a 2.2.x kernel does not need a patch. On Mandrake 6.1, the required RAID modules were already in place after installation. Bill Carlson Systems Programmer[EMAIL PROTECTED]| Opinions are mine, Virtual Hospital http://www.vh.org/| not my employer's. University of Iowa Hospitals and Clinics|
Re: mkraid aborts, no info?
On Wed, 27 Oct 1999, David A. Cooley wrote: Hi Bill, You need to get the latest raid kernel patch (ignore the errors it gives... one hunk is included in the 2.2.12/2.2.13 kernel) and the latest raidtools (0.90). Ah, I see now. I'll try applying the patch to the 2.2.13 now. Thanks David, Luca. Bill Carlson Systems Programmer[EMAIL PROTECTED]| Opinions are mine, Virtual Hospital http://www.vh.org/| not my employer's. University of Iowa Hospitals and Clinics|
raid0145 patch
Hey, The patch did the trick, just like it was supposed to. cd /usr/src/linux patch -p1 raid0145-19990824-2.2.11 There was the one error, which I ignored, as I was patching against 2.2.12. Does the same patch apply vs 2.2.13? I'm guessing that Mandrake's sources are what caused the errors that lead me to go with a fresh 2.2.12 source tree. Recompile, reboot and the magic messages started. :) 2 minutes later I had me an 8 GB array. Thanks a lot everyone! Bill Carlson Systems Programmer[EMAIL PROTECTED]| Opinions are mine, Virtual Hospital http://www.vh.org/| not my employer's. University of Iowa Hospitals and Clinics|
