Re: Replacing a RAID-1 mirror drive
On Wed, 10 Nov 1999, Matt Kimmel wrote: Hi all, I am running a RAID-1 mirror set of two disks on our Linux server here. A couple of weeks ago, one of the mirrors went bad. While waiting for a replacement, I ran the mirror with a single drive, which worked fine. However, now that I have a replacement drive, I can't seem to add it back into the mirror group. Here's my /etc/raidtab: raiddev /dev/md0 raid-level 1 nr-raid-disks 2 nr-spare-disks 0 chunk-size 4 device /dev/sda1 raid-disk 0 device /dev/sdd1 raid-disk 1 And here's the kernel message I get when /dev/md0 is started: Partition check: sda: sda1 sdb: sdb1 sdc: sdc1 sdd: sdd1 md.c: sizeof(mdp_super_t) = 4096 hda: hda1 hda2 hda5 hda6 autodetecting RAID arrays (read) sda1's sb offset: 17775808 [events: 002d] autorun ... considering sda1 ... adding sda1 ... created md0 bindsda1,1 running: sda1 now! sda1's event counter: 002d md0: max total readahead window set to 128k md0: 1 data-disks, max readahead per data-disk: 128k raid1: device sda1 operational as mirror 1 raid1: md0, not all disks are operational -- trying to recover array raid1: raid set md0 active with 1 out of 2 mirrors md: updating md0 RAID superblock on device sda1 [events: 002e](write) sda1's sb offset: 17775808 considering sda1 ... adding sda1 ... created md0 bindsda1,1 running: sda1 now! sda1's event counter: 002d md0: max total readahead window set to 128k md0: 1 data-disks, max readahead per data-disk: 128k raid1: device sda1 operational as mirror 1 raid1: md0, not all disks are operational -- trying to recover array raid1: raid set md0 active with 1 out of 2 mirrors md: updating md0 RAID superblock on device sda1 [events: 002e](write) sda1's sb offset: 17775808 md: recovery thread got woken up ... md0: no spare disk to reconstruct array! -- continuing in degraded mode ^^^ you have to add a spare disk to get it to work Uwe
Re: Re: anyone knows?
I meant add some other raid architecture such as EvenOdd, P+Q to linux-raid. At 99-11-11 3:13:00, you wrote: What exactly do you wish to 'create'? I would suggest doing some reading on RAID - past, present and future - and propose your own architecture if you feel you have something to add.
Re: adding/removing linear raid drives
Jakob, On Wed, 10 Nov 1999 19:55:56 +0100, Jakob stergaard wrote: After a change you can mkraid the array again, and if you have an ext2 filesystem on it, you can probably use ext2resize to resize that to fit the new size of the array. Note however, that ext2resize only supports *growing* filesystems. You're out of luck for shrinking. That's not _my_ experience. I tried it last weekend with what I found on http://www.dsv.nl/ ~buytenh/ext2resize (1.0.5 or so) and it happily shrinks ext2 filesystems. Regards, Robert
Re: adding/removing linear raid drives
Well, thanks for the hints, it didnt work, this is what i did. Backed up some of the array. (this became boring so i decided to run the gauntlet) A tip for beginners, when creating linear arrays make the biggest array the first one, not the last one. Tried to defragment the md array, defrag doesnt work on md arrays :-[ (why?) Edited /etc/raidtab to remove any mention of the last drive Ran mkraid, had to do the scary mkraid --really-force, so at this stage i was loosing confidence. Halted, removed the last drive, restarted This is where the shit started to hit the fan. I probably should have changed the partition types back from fd to 83 as when i rebooted it tried to autodetect the array and check it. So it dropped me into maintanace mode Tried doing e2fsck /dev/md1 and naturally got a heap of errors regarding access beyond end of device This went on forever, so i just stoped and tried to mount it, just locked up the term. I actually got a segmentation fault in here somewhere. Tried shuting down but all device couldnt be unmounted (because the mount command hung i guess) Hard reboot. I should have tried using fsresize to shrink the array, maybe this would have prevented the above problems. (do you think?) Anyway ill remeber that for next time. My thoughts on doing a defrag was that defrag would move all the data to the start of the array, and thus the drive that i removed should contain no data. Did i have the right idea here? Anyway its all a learning process for me, so the data loss is no big deal. Maybe this info is usefull for someone Glenn McGrath
Re: Replacing a RAID-1 mirror drive
On Thu, 11 Nov 1999, Uwe Schmeling wrote: On Wed, 10 Nov 1999, Matt Kimmel wrote: Hi all, I am running a RAID-1 mirror set of two disks on our Linux server here. A couple of weeks ago, one of the mirrors went bad. While waiting for a replacement, I ran the mirror with a single drive, which worked fine. However, now that I have a replacement drive, I can't seem to add it back into the mirror group. Here's my /etc/raidtab: raiddev /dev/md0 raid-level 1 nr-raid-disks 2 nr-spare-disks 0 chunk-size 4 device /dev/sda1 raid-disk 0 device /dev/sdd1 raid-disk 1 That should be fine... autodetecting RAID arrays At this point, the kernel scans all detected partitions for type `0xfd`.When you created the new /dev/sdd1 partition, did you set its type to 'fd'? If not, then you have your answer. (read) sda1's sb offset: 17775808 [events: 002d] autorun ... considering sda1 ... adding sda1 ... created md0 Here is my same entry section: autodetecting RAID arrays (read) sdb1's sb offset: 8883840 [events: 005a] (read) sdc1's sb offset: 8883840 [events: 005a] autorun ... considering sdc1 ... adding sdc1 ... adding sdb1 ... created md0 Cheers! Chris
Re: adding/removing linear raid drives
On Thu, Nov 11, 1999 at 01:40:07PM +1000, Glenn McGrath wrote:
Well, thanks for the hints, it didnt work, this is what i did.
Backed up some of the array. (this became boring so i decided to run the
gauntlet)
A tip for beginners, when creating linear arrays make the biggest array the
first one, not the last one.
Tried to defragment the md array, defrag doesnt work on md arrays :-[ (why?)
There should be no reason why defrag can't use md arrays. Write the defrag
maintainer if it's really a problem.
Edited /etc/raidtab to remove any mention of the last drive
Ran mkraid, had to do the scary mkraid --really-force, so at this stage i
was loosing confidence.
Halted, removed the last drive, restarted
If you had a filesystem on your md device, the md device is now smaller,
but your filesystem still thinks it sits on a larger device.
This was shy I mentioned ext2resize, and why I mentioned that ext2resize
cannot shrink filesystems, only grow them. If it sounded like you didn't
need to shrink the filesystem before shrinking the device it resides on,
them I'm very sorry about that. But filesystems _must_ be resized when
the devices they reside on are resized, for the changes to work on all
layers (fs+block).
When shrinking: shrink filesystem (currently impossible AFAIK)
shrink device
When growing:grow device (using your method for linear arrays and
raidreconf for raid-0 arrays)
grow filesystem
By the way, I managed to grow a raid-0 from around 50G to around the
double, using raidreconf and ext2resize. raidreconf is slow as molasses
but it all went well, even though it took something like 24 hours.
This is where the shit started to hit the fan.
I probably should have changed the partition types back from fd to 83 as
when i rebooted it tried to autodetect the array and check it.
So it dropped me into maintanace mode
It dropped you into maintenance mode because your filesystem couldn't be
mounted, because the last N megabytes/gigabytes of your ``disk'' (md device)
was suddenly missing.
Tried doing e2fsck /dev/md1 and naturally got a heap of errors regarding
access beyond end of device
Sounds reasonable, considering the situation.
This went on forever, so i just stoped and tried to mount it, just locked up
the term.
I actually got a segmentation fault in here somewhere.
I'm sure the ext2fs tools maintainer would like to hear about that.
Tried shuting down but all device couldnt be unmounted (because the mount
command hung i guess)
Hard reboot.
Removing the md device from the fstab should give you a clean boot.
I should have tried using fsresize to shrink the array, maybe this would
have prevented the above problems. (do you think?)
Anyway ill remeber that for next time.
You can't shrink/grow md devices using a filesystem resizing tool. Just like
you filesystem is not magically resized when you use a md device resizing
tool (or do it manually).
Remember, there is no connection between an md device and a filesystem other
than that a md device is a block device which _can_ contain a filesystem (any
filesystem) and that filesystems usually reside on block devices.
I'm very sorry that this wasn't clearer before.
My thoughts on doing a defrag was that defrag would move all the data to the
start of the array, and thus the drive that i removed should contain no
data.
Did i have the right idea here?
Definitely. The problem was that the ext2 filesystem still thinks that it
has all the space available from your old array.
Anyway its all a learning process for me, so the data loss is no big deal.
I'm glad to hear that.
Maybe this info is usefull for someone
Once I get some more work done on raidreconf, maybe a section should be
added to the HOWTO about resizing arrays.
Thanks for the feedback,
--
: [EMAIL PROTECTED] : And I see the elder races, :
:.: putrid forms of man:
: Jakob Østergaard : See him rise and claim the earth, :
:OZ9ABN : his downfall is at hand. :
:.:{Konkhra}...:
Re: Abort
On Thu, Nov 11, 1999 at 01:49:51AM +0100, Zsiga Robert wrote:
I have a problem.
I would like to create a "raid arrays".I have two SCSI disks.I would like
to use the RAID0 mode.When i mkraid /dev/md0 , mkraid aborted.
Why?
The /etc/raidtab file is the sample file for RAID0.The -f --really-force
don't help.Neither if i recreate the partitions.The second problem the
mkraid write that the partitions consist ext2.
What can i do???
Help me!
What kernel ? One with raid patches or not ? Which raidtools version ?
We need to see the raidtab to help you.
--
: [EMAIL PROTECTED] : And I see the elder races, :
:.: putrid forms of man:
: Jakob Østergaard : See him rise and claim the earth, :
:OZ9ABN : his downfall is at hand. :
:.:{Konkhra}...:
Performance .... MegaRAID
Guys n gals, Does anyone here use a MegaRAID Hardware RAID controller? If yes, what is your performance like? On a 500Mb file copy (from sda - sda) we get around 2.5Mb per second.. it seems very low. At worst, we have had 456k per sec. Regards, Matthew Clark. -- NetDespatch Ltd - The Internet Call Centre. http://www.netdespatch.com
Re: Performance .... MegaRAID
Matthew Clark wrote: Does anyone here use a MegaRAID Hardware RAID controller? If yes, what is your performance like? On a 500Mb file copy (from sda - sda) we get around 2.5Mb per second.. it seems very low. At worst, we have had 456k per sec. On my MegaRAID 428 w/ 8meg RAM I get 10.5meg/sec with 64k striping on 2 UW drives. It appears the controller max out at 10.5megs/sec as I tried 2 striping setups with 3 different drives and got the same results. (speeds are single drive on a UW Mylex BT-958 controller) - IBM 4gig U2W: 12.5meg/sec - Seagate 4gig W: 4.5meg/sec - IBM 9gig U2W: 17.5meg/sec I tried the IBM 4gig with each of the other 2 drives and still got 10.5meg/sec (hdparm). Brian Macy
Re: Offtopic: LVD U2W drives on UW SCSI-3 controller
Hi; Sorry about the somewhat offtopic question, but I have a supplier of mine trying to tell me that LVD U2W dries will work on my Symbios 53C875 UW SCSI-3 controller. Will LVD U2W drives work on a UW controller? I thought that LVD was quite different than other forms of scsi. The Quantum Atlas 10K drives that I use have a jumper to select LVD or SE. I have used them in both modes (with the appropriate controller) with no problems.
Re: Offtopic: LVD U2W drives on UW SCSI-3 controller
Jonas Diener wrote: Hi; Sorry about the somewhat offtopic question, but I have a supplier of mine trying to tell me that LVD U2W dries will work on my Symbios 53C875 UW SCSI-3 controller. Will LVD U2W drives work on a UW controller? I thought that LVD was quite different than other forms of scsi. The Quantum Atlas 10K drives that I use have a jumper to select LVD or SE. I have used them in both modes (with the appropriate controller) with no problems. i just bought 1 of each IBM, Quantum, WD, and Seagate 10k drives and they all seem to support the backwards compatible feature.
RE: MegaRAID vs Mylex
I am getting on my RAID5 array of 8 7200RPM seagate barracuda 18.2GB drives around 30MB/S writting and 49MB/S Reading -- Brian D. Haymore University of Utah Center for High Performance Computing 155 South 1452 East RM 405 Salt Lake City, Ut 84112-0190 Email: [EMAIL PROTECTED] - Phone: (801) 585-1755 - Fax: (801) 585-5366 On Thu, 11 Nov 1999, Matthew Clark wrote: Hi there, what sort of performance have you had from the Mylex on Linux? I'm looking at copying/writing 500Mb files (internal).. our megaraid runs at about 2Mb per sec... -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Brian D. Haymore Sent: 11 November 1999 22:16 To: Matthew Clark Cc: linux-scsi; linux-raid Subject: Re: MegaRAID vs Mylex Mylex does from my tests. Mylex does very well in fact. -- Brian D. Haymore University of Utah Center for High Performance Computing 155 South 1452 East RM 405 Salt Lake City, Ut 84112-0190 Email: [EMAIL PROTECTED] - Phone: (801) 585-1755 - Fax: (801) 585-5366 On Thu, 11 Nov 1999, Matthew Clark wrote: Which gives better performance on Linux??? Regards, Matthew Clark. -- NetDespatch Ltd - The Internet Call Centre. http://www.netdespatch.com - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [EMAIL PROTECTED]
MegaRAID vs Mylex
Which gives better performance on Linux??? Regards, Matthew Clark. -- NetDespatch Ltd - The Internet Call Centre. http://www.netdespatch.com
Re: MegaRAID vs Mylex
Mylex does from my tests. Mylex does very well in fact. -- Brian D. Haymore University of Utah Center for High Performance Computing 155 South 1452 East RM 405 Salt Lake City, Ut 84112-0190 Email: [EMAIL PROTECTED] - Phone: (801) 585-1755 - Fax: (801) 585-5366 On Thu, 11 Nov 1999, Matthew Clark wrote: Which gives better performance on Linux??? Regards, Matthew Clark. -- NetDespatch Ltd - The Internet Call Centre. http://www.netdespatch.com
RE: MegaRAID vs Mylex
Hi there, what sort of performance have you had from the Mylex on Linux? I'm looking at copying/writing 500Mb files (internal).. our megaraid runs at about 2Mb per sec... -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Brian D. Haymore Sent: 11 November 1999 22:16 To: Matthew Clark Cc: linux-scsi; linux-raid Subject: Re: MegaRAID vs Mylex Mylex does from my tests. Mylex does very well in fact. -- Brian D. Haymore University of Utah Center for High Performance Computing 155 South 1452 East RM 405 Salt Lake City, Ut 84112-0190 Email: [EMAIL PROTECTED] - Phone: (801) 585-1755 - Fax: (801) 585-5366 On Thu, 11 Nov 1999, Matthew Clark wrote: Which gives better performance on Linux??? Regards, Matthew Clark. -- NetDespatch Ltd - The Internet Call Centre. http://www.netdespatch.com - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [EMAIL PROTECTED]
