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Author Topic: Any Raid Experts?  (Read 5036 times)

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Offline Piru

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Re: Any Raid Experts?
« Reply #29 from previous page: July 03, 2010, 02:11:37 PM »
I just had my first HDD failure with the RAID-5. One of the 1.5TB Barraducas (ST31500541AS) dropped dead. I've swapped the drive and added the new HDD to the array with:
Code: [Select]
sudo mdadm /dev/md0 --add /dev/sdh1The raid is now rebuilding itself:
Code: [Select]
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sdh1[3] sdb1[0] sdg1[2]
      2930276864 blocks level 5, 128k chunk, algorithm 2 [3/2] [U_U]
      [=>...................]  recovery =  8.0% (117313844/1465138432) finish=516.8min speed=43460K/sec
     
unused devices:
This is the critical part. If the rebuilding fails due to failure in the remaining good drives I will lose the array and all data within. If it was RAID-6 I could still lose a 2nd disk without data loss.

Obviously I've backed up all important data before the rebuild, so only some less important data would be lost if 2nd disk failure should occur.
« Last Edit: July 03, 2010, 02:19:49 PM by Piru »
 

Offline bbond007

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Re: Any Raid Experts?
« Reply #30 on: July 03, 2010, 06:29:13 PM »
Quote from: sknight;566892
Raid doesn't guarantee your data integrity. It doesn't detect silent data corruption for instance.
At present the best solution to preserve your data is to use ZFS as filesystem.


What about ReiserFS - I heard is was a killer filesystem.
 

Offline BinoX

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Re: Any Raid Experts?
« Reply #31 on: July 03, 2010, 06:34:15 PM »
Quote from: bbond007;568800
What about ReiserFS - I heard is was a killer filesystem.


That's funny...  but it really shouldn't be
Back to action!
 

Offline gertsy

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Re: Any Raid Experts?
« Reply #32 on: July 04, 2010, 12:46:52 PM »
Quote from: trekiej;567071
Thanks.
An Article I was reading said that the user should have Backup Storage in case of a raid failure.
It also said ( or another post ) that cost wise that Raid 1+0 was better than Raid5 on the second disk failure.
For a newbie, it looks like the Holy Grail, when it fails it becomes a Holy Cow. :)
The board I want to get has 6Gbs SATA. How can I push that to the limit?  
Do I need SSD's or many HD's?
Can a raid system beat the bloat? :)


I remember this review when I last upgraded in 2007.  

http://www.tomshardware.com/reviews/cheap-raid-ravages-wd-raptor,1562.html

Using 2 raptors 0+1 was pretty impressive.  And still is..

@sknight, ZFS ?  Ur kidding me.  With ZFS (pooled) you don't know the impact of a drive failure as you dont know which drive has which data.  Very handy.  Thats why Symantec(Veritas) make so much money on Sun.
« Last Edit: July 04, 2010, 12:50:56 PM by gertsy »
 

Offline sknight

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Re: Any Raid Experts?
« Reply #33 on: July 06, 2010, 06:44:48 AM »
Quote from: bbond007;568800
What about ReiserFS - I heard is was a killer filesystem.
AFAIK Reiser FS doesn't have all the benefits of ZFS. BTR is the only filesystem with the same ZFS characteristics  but it's not ready yet (or better saying, tested enough).



As for the killer filesystem statement, that's the explanation:
http://www.theregister.co.uk/2008/07/08/body_found_reiser/

« Last Edit: July 09, 2010, 07:09:26 PM by sknight »
 

Offline sknight

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Re: Any Raid Experts?
« Reply #34 on: July 06, 2010, 07:04:36 AM »
Quote from: gertsy;568908
@sknight, ZFS ?  Ur kidding me.  With ZFS (pooled) you don't know the impact of a drive failure as you dont know which drive has which data.  Very handy.  Thats why Symantec(Veritas) make so much money on Sun.

No, you are kidding me! You don't need to know where your data is. You just need to know which drive has a failure in order to replace it... ZFS shows clearly which drive has checksum errors. Then you just need to replace the disk.

Take a look at this video: http://www.youtube.com/watch?v=QGIwg6ye1gE

Two drives are literally destroyed during a live demonstration with no data loss. Try that with RAID-5! :-)

This video is very interesting too and shows how zfs detects silent data corruption (something that RAID doesn't!!!):

http://hub.opensolaris.org/bin/view/Community+Group+zfs/selfheal
« Last Edit: July 06, 2010, 07:16:36 AM by sknight »
 

Offline Marcb

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Re: Any Raid Experts?
« Reply #35 on: July 06, 2010, 12:16:17 PM »
And there I was ready to share my River Raid playing tips.

Misleading subject. Bah
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Offline trekiejTopic starter

Re: Any Raid Experts?
« Reply #36 on: July 12, 2010, 06:02:44 AM »
lol
I have not seen RiverRaid in a long time.
I am not really settled on which Raid to use.
I will have to try both Raid5 and Raid 1+0 some day.
Raid! as the bug spray commercial goes.
Amiga 2000 Forever :)
Welcome to the Planar System.
 

Offline ElPolloDiabl

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Re: Any Raid Experts?
« Reply #37 on: August 27, 2010, 05:14:54 PM »
I'm running Raid 0 with an external drive for backup. They are both Seagate 7200RPM drives and the speed is between 200-243 MB/s both reading and writing.
The biggest plus is that it removes (lessens) the hard drive bottle neck. Anything writing to the hard drive has less time to wait.
If you want serious speed go for 2 SSDs (or 4 for 0+1) that will eliminate the long seek times as well.
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