Mailinglist Archive: opensuse (963 mails)

[Per Jessen <per@xxxxxxxxxxxx>]

David Haller wrote:

> Hello,
>
> sorry it took me so long to reply.
>
> On Tue, 12 Apr 2011, Per Jessen wrote:
> > I would probably make a number of RAID1 arrays of equal-size disks,
> > then use LVM for managing the space.
>
> RAID1 as underlying RAID-Level would be to wasteful for my data. 

It's not only about the data, it's also about availability and uptime. 
Maybe that's irrelevant to you, I don't know.  Never mind, if CHF100
for a 2nd 2Tb drive is too much, and you're happy with a restore of
yesterdays backup to the new drive (once you've bought it), RAID1 is
wasteful, I agree.

> RAID5 would be nice if I could span volumes sanely across my (often
> changing) disks ...

"span volumes"?  
Changing disks is only a practical matter, plus the time it takes to
rebuild the array after a change.  

> > If I needed RAID6, I would have to do with the smallest disk-size, but
> > otherwise I don't see a problem.
>
> So, what'd you make out of:
>
> [0:0:0:0]    disk    ATA      SAMSUNG HD501LJ  CR10  /dev/sda   # .5T
> [1:0:0:0]    disk    ATA      SAMSUNG HD204UI  1AQ1  /dev/sdb   # 2T
> [2:0:0:0]    disk    ATA      ST31500341AS     CC1H  /dev/sdc   # 1.5T
> [3:0:0:0]    disk    ATA      SAMSUNG HD203WI  1AN1  /dev/sdd   # 2T
> [4:0:0:0]    disk    ATA      SAMSUNG HD203WI  1AN1  /dev/sde   # 2T
> [5:0:0:0]    disk    ATA      SAMSUNG HD203WI  1AN1  /dev/sdf   # 2T
> [8:0:0:0]    disk    ATA      SAMSUNG HD204UI  1AQ1  /dev/sdg   # 2T
> [9:0:0:0]    disk    ATA      SAMSUNG HD204UI  1AQ1  /dev/sdh   # 2Y
> [16:0:1:0]   disk    ATA      WDC WD5000AVJB-6 05.0  /dev/sdi   # .5T

I would create a RAID6 on sdb, sdd, sde, sdf, sdg, sdh.  That would give
you an 8Tb array with dual drive redundancy.  
With 2Tb drives, recovering after a drive failure can be quite slow,
giving plenty of time for a 2nd drive to fail.  Your Samsung drives are
relatively cheap desktop drives, so likely to fail exactly when the
warranty expires :-(
Alternatively, if dual-drive redundancy is too wasteful, a RAID5 over
the same drives would give you 10Tb.
Then I would probably run a RAID1 on sda and sdi for system etc etc. 

> and that's rather recently, until a few months ago that was a merry
> mix of .5T, .75T, 1T, 1.5T and 2T ... Oh, and only /dev/sda (current
> system disk for a SUSE and a Gentoo), /dev/sdb (newest disk, prepped
> for 2 system-roots w/o home[1] to replace sda sometime), and /dev/sdg
> (one "home2" partition for basically replacable "home" stuff, one
> "data" partition). The rest is data partitions (one each disk). Oh,
> and expect disks being replaced by e.g. 3T drives soonish.

With a forever changing setup like that, LVM sounds like just what you
need. 


-- 
Per Jessen, Zürich (9.6°C)

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