Date: Mon, 04 Jun 2012 21:53:01 +0100 From: Kaya Saman <kayasaman@gmail.com> To: Johan Hendriks <joh.hendriks@gmail.com> Cc: freebsd-fs@freebsd.org Subject: Re: Using ZFS as RAID0 - disk offline question Message-ID: <4FCD202D.2060601@gmail.com> In-Reply-To: <4FCD1F00.5080805@gmail.com> References: <4FCD13CF.3010406@gmail.com> <4FCD17C6.5020503@FreeBSD.org> <4FCD19E6.1010802@gmail.com> <4FCD1F00.5080805@gmail.com>
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On 06/04/2012 09:48 PM, Johan Hendriks wrote: > Kaya Saman schreef: >> On 06/04/2012 09:17 PM, Matthew Seaman wrote: >>> On 04/06/2012 21:00, Kaya Saman wrote: >>>> in ZFS when using a simple RAID 0 style array is there a way to >>>> recover >>>> a pool after a disk has gone down? >>> No. RAID0 has no resilience to disk failure. That's why things like >>> RAID1, RAID10, RAIDz, RAIDz2 exist: so that your data will survive >>> failure of some number of the drives it is stored on. >>> >>> Make sure you have good backups, basically. >>> >>> Cheers >>> >>> Matthew >>> >> >> Thanks for the responses! >> >> >> I wasn't actually meaning recovering data on the 'downed' disk but on >> the disk that was still online...... >> >> >> You see if say a system board fails and both devices are named >> /dev/ad4 and /dev/ad5 then a new system board gets put in and the >> device names changed to /dev/ad12 and /dev/ad13 my question is will >> the ZPOOL still exist? Will ZFS be intelligent enough to pick up the >> new device names via the disk ID's? >> >> >> Additionally if /dev/ad5 goes down, is it possible to keep using >> /dev/ad4 which is part of the 'downed' pool...?? Or would one need to >> replace the disk ad5 then the pool comes up again with only the >> information on ad4?? >> >> >> This is what I was trying to get at and sorry if I didn't understand >> 100% the direction of the responses! >> >> As in if you meant that the information of on /dev/ad5 will be lost - >> I do understand this :-) >> >> >> Regards, >> >> Kaya >> _______________________________________________ >> freebsd-fs@freebsd.org mailing list >> http://lists.freebsd.org/mailman/listinfo/freebsd-fs >> To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org" > you can not loose a disk from a raid0 period. > To put it simple, your files are split in half, one part is copied to > disk 1 and the other part on disk2 . > So without the two copies no files, no data. > > If device names changes because of a hardware change, the pool schould > be importable. > But both disks need to be there. > Raid0 should be avoided if possible, better add one disk extra and > create a raidz. > > regards > Johan Hendriks > Yeah, I'm starting to see this now! Of course I don't think it's possible to upgrade from RADI0 to RAIDZ.... Easier to go to RAID1 which gives most protection. Though is not the most efficient method of doing things. Regards, Kayahome | help
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