software raid drive failed, please provide step bu steptorebuild
Dan Carl
danc at bluestarshows.com
Sat Jul 29 00:37:15 UTC 2006
Ok I totally see your point about striping my swap partition.
I read it some howto a few years back.
I did just what you said
I paritioned my new drive the exact same as the other two.
I issued the command
mdadm /dev/md2 -a /dev/sdc3
and the raid md2 is rebuilding as I write this.
So how do I get setup my swap as you described?
Now I have three drives w/ partition
265072 sda2
265072 sdb2
265072 sdc2
Thank you soooo much
Its 100 degrees, its Friday and now I have go outside and mow my lawn.
Look forward to reading your reply while sipping a cold one!
----- Original Message -----
From: "Jeff Vian" <jvian10 at charter.net>
To: "For users of Fedora Core releases" <fedora-list at redhat.com>
Sent: Friday, July 28, 2006 6:48 PM
Subject: Re: software raid drive failed, please provide step bu
steptorebuild
> On Fri, 2006-07-28 at 18:03 -0500, Dan Carl wrote:
>> I know its a raid 0 is a stripe.
>> Its my swap partition.
>> Why would I need fault tolerance on my swap.
>>
>>From your first post below:
> Now I can reach the drive via fdisk but I have made more
> problems now (no swap now)
> and I'm not sure the steps to rebuild.
> That is a good reason to make sure that vital disk partitions are not
> made critically weak. When striping across 3 drives the failure
> probability is made 3X as likely and any single failure toasts the
> entire device.
>
> Since swap can use multiple partitions the likelyhood of failure and
> total loss of swap space can be reduced by simply defining multiple swap
> partitions without using striping.
>
>
>
>> Anyway,
>> I did what Sam suggested.
>> md0 is fine, md1 doesn't exist
>> mdadm -Q -D /dev/md2
>> it yeilded
>> /dev/md2:
>> Version : 00.90.01
>> Creation Time : Mon Feb 14 06:42:28 2005
>> Raid Level : raid5
>> Array Size : 34812416 (33.20 GiB 35.65 GB)
>> Device Size : 17406208 (16.60 GiB 17.82 GB)
>> Raid Devices : 3
>> Total Devices : 2
>> Preferred Minor : 2
>> Persistence : Superblock is persistent
>> Update Time : Fri Jul 28 17:56:25 2006
>> State : clean, degraded
>> Active Devices : 2
>> Working Devices : 2
>> Failed Devices : 0
>> Spare Devices : 0
>> Layout : left-symmetric
>> Chunk Size : 256K
>> Number Major Minor RaidDevice State
>> 0 8 3 0 active sync /dev/sda3
>> 1 8 19 1 active sync /dev/sdb3
>> 2 0 0 -1 removed
>> UUID : b4b161bc:2953b117:9c13c568:47693baa
>> Events : 0.31307539
>>
> So mdadm -a needs to be used to add the 3rd device back to md2. Sam's
> instructions were clear on that. For more information and education use
> the man page for mdadm.
>
>
> MANAGE MODE
> Usage: mdadm device options... devices...
> This usage will allow individual devices in an array to be
> failed,
> removed or added. It is possible to perform multiple
> operations with
> one command. For example:
> mdadm /dev/md0 -f /dev/hda1 -r /dev/hda1 -a /dev/hda1
> will firstly mark /dev/hda1 as faulty in /dev/md0 and will then
> remove
> it from the array and finally add it back in as a spare.
> However only
> one md array can be affected by a single command.
>
>
> I would do the following that you have not already stated done.
> 1. create the partition(s) on your new /dev/hdc
> 2. use mdadm as follows to add it to md2
> mdadm /dev/md2 -a /dev/sdc3
> note that I assume your partitions are created and numbered as you have
> already stated.
>
>> What if the next step this is my mail server and I really don't have the
>> time to reload it.
>> I have my fstab, partition, mdstat, infomation.
>> I ran this command sfdisk -d > sdb-parts.dump before a added the new
>> drive.
>> Will any of this help?
>>
> fdisk -l will list the partition information for each drive including
> start and end cylinders such as this.
>
> [root at raptor pgsql]# fdisk -l /dev/hda
>
> Disk /dev/hda: 250.0 GB, 250059350016 bytes
> 255 heads, 63 sectors/track, 30401 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
>
> Device Boot Start End Blocks Id System
> /dev/hda1 * 1 21 168651 83 Linux
> /dev/hda2 22 532 4104607+ 83 Linux
> /dev/hda3 533 721 1518142+ 82 Linux
> swap
> /dev/hda4 722 30401 238404600 5 Extended
> /dev/hda5 722 1359 5124703+ 83 Linux
> ....
>
>>From that you can get not only the size of each partition, but the
> actual cylinders used and can recreate the table on the new drive
> appropriately with fdisk.
>
>
>> Like I said before the only raid/partition experience I have is at
>> initial
>> installation.
>>
>>
>>
>> ----- Original Message -----
>> From: "Jeff Vian" <jvian10 at charter.net>
>> To: "For users of Fedora Core releases" <fedora-list at redhat.com>
>> Sent: Friday, July 28, 2006 5:44 PM
>> Subject: Re: software raid drive failed, please provide step bu step
>> torebuild
>>
>>
>> > On Fri, 2006-07-28 at 16:29 -0500, Dan Carl wrote:
>> > > I have/had a software raid running and sdc drive failed.
>> > > I got a replacement drive today and installed it.
>> > > My only experience with set partitions and raids in during initail
>> setup.
>> > > I could not fdisk the new drive because i guess it wasn't reconized
>> > > so I
>> > > rebooted.
>> > > Now I can reach the drive via fdisk but I have made more problems now
>> (no
>> > > swap now)
>> > > and I'm not sure the steps to rebuild.
>> > > Background:
>> > > I have a FC3 with a software raid.
>> > > I have 3 SCSI 18gb hard drives
>> > > If I recall this how I set it up
>> > > md0 /boot 100MB raid 1 sda, sdb and sdc as spare
>> > > md1 /swp 768MB raid 0 sda, sdb, sdc
>> > This toasted your /swp partition.
>> > Raid 0 is striping, and a single failure toasts the entire device.
>> >
>> > You would have been ahead with a non-raid swap, and had 3 separate
>> > partitions, one on each device, for swap. Failure of one would not
>> > have
>> > toasted all.
>> >
>> >
>> > > md2 / ext3 33GB raid 5 sda, sdb, sdc
>> > >
>> > > Can someone please help?
>> > >
>> >
>> > --
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>>
>
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