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Old 10-15-2012, 01:11 AM   #1
ivertobson
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RAID 5 failed due to hard drive failure(Lost Data of national importance!)


I have dell poweredge server with 8 hard drives(250GB each). The system was running in Fedora 11. The database on the system contains extremely important. I used to back up the data manually in a different drive as well as through crontab. Now suddenly two hard drives failed and the system wont reboot. I got my live data there and i would like to recover.
I'm using knoppix and want to recover the data. But i'm not able to.
I've also ordered two new hard drive from dell, it has arrived. Do i remove the failed hard drive and insert the new ones and then recover using the knoppix? or the other way round?.
When i boot with knoppix, and when i do "fdisk -l", it doesn't show any information.
Can you please help me out on this? Thanks..
 
Old 10-15-2012, 07:02 AM   #2
chrism01
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I've got bad news for you

1. Fedora is RedHat's R&D, bleeding edge unstable distro, used to test tech that may(!) end up in RHEL.
If you're serious about the importance of your data, you are definitely(!) using the wrong distro.
If you like RH, either pay for it, or get Centos, a free rebuild of RHEL.
BTW, Fedora 11 hasn't been updated in a while, they're currently on F17

2. if you read the following, you'll find that RAID5 is only specc'ed to survive a single disk failure. RAID6 should survive 2 disks dying.
I think you'll have to go to your backups
https://en.wikipedia.org/wiki/RAID
https://en.wikipedia.org/wiki/Standard_RAID_levels
 
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Old 10-15-2012, 07:02 AM   #3
chrism01
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I've got bad news for you

1. Fedora is RedHat's R&D, bleeding edge unstable distro, used to test tech that may(!) end up in RHEL.
If you're serious about the importance of your data, you are definitely(!) using the wrong distro.
If you like RH, either pay for it, or get Centos, a free rebuild of RHEL.
BTW, Fedora 11 hasn't been updated in a while, they're currently on F17

2. if you read the following, you'll find that RAID5 is only specc'ed to survive a single disk failure. RAID6 should survive 2 disks dying.
I think you'll have to go to your backups
https://en.wikipedia.org/wiki/RAID
https://en.wikipedia.org/wiki/Standard_RAID_levels
 
1 members found this post helpful.
Old 10-15-2012, 04:22 PM   #4
jefro
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Might help if you post more info as to how you created the raid array and what controls it. Normally raid 5 does not recover from three disk with two fail but you will have to tell us. If this is hardware raid then maybe you can still use it's functions at boot to control the repair.

Knoppix is a poor choice to use on servers. I'd be more inclined to boot to an opensuse or suse 9/10/11 cd/dvd.
 
Old 10-15-2012, 04:38 PM   #5
JaseP
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If the data is of national importance, then the Gov't can pay for forensic data recovery,... and better to let a qualified forensic data recovery team get the data back than having you muck about and destroy the data.

If it is evidence,... as in a criminal trial,... A forensic data recovery firm can recover the data while preserving the chain of custody.

If it is military/nat'l intelligence in nature, there are firms with the necessary clearances, I'm sure...

If it's civilian in nature, potentially less damaging if the data is lost, but still,... this is the kind of thing that forensic firms will have NDAs about.

If it's political in nature,... it probably wasn't important anyway!!!
 
Old 10-15-2012, 07:25 PM   #6
NyteOwl
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RAID 5 as stated is not spec'd to recover from more than a single drive failure per array. Also as stated, critical systems should not be running test bed operating systems. RHEL, SUSE Enterprise, Slackware, CentOS, Debian(stable), Free/OpenBSD are all viable options for reliable server operations.

You may be able to recover by replacing the failed drives one at a time and seeing if the array will rebuild. However, with critical data I'd look to your backups.

If the data is that important, it's time to replace the entire array, restore data backups, preserve the old array drives and contact a data recovery firm. I'd also consider moving to a more redundant array mode such as 6, 10 or 50/60.
 
Old 10-15-2012, 08:14 PM   #7
suicidaleggroll
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Sorry, but the data is gone. RAID 5 only has one parity drive for the array, which means you can only lose one drive and still be protected. When you lose two or more drives in a RAID 5 system, you lose the entire array. 8 drives is simply too many for RAID 5 unless you have a hot spare ready to go in my opinion. The chances of losing two drives within the rebuild cycle is too great. For arrays that large you should really be using RAID 6 at a bare minimum.
 
Old 10-15-2012, 09:50 PM   #8
JaseP
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Not necessarily so... Regardless of the situation, a forensics firm can pull the data off the drive and attempt to reconstruct it. Complicated by the array structure, for sure. If the failure was hardware, like the loss of hardware components as a result of a bad power supply,... a forensic firm can replace the electronics or just pull the bits off the platter. Some of these firms can pull off data that's been overwritten several times from a drive...

Don't underestimate them...

Oh,... and here;
http://computersciencelabs.blogspot.com/

Last edited by JaseP; 10-15-2012 at 09:57 PM.
 
  


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