On 20/01/2010 19:20, Ian Collins wrote:
Julian Regel wrote:
>It is actually not that easy.
>
>Compare a cost of 2x x4540 with 1TB disks to equivalent solution on
LTO.
>
>Each x4540 could be configured as: 4x 11 disks in raidz-2 + 2x hot
spare
>+ 2x OS disks.
>The four raidz2 group form a single pool. This would provide well over
>30TB of logical storage per each box.
>
>Now you rsync all the data from your clients to a dedicated filesystem
>per client, then create a snapshot.
>All snapshots are replicated to a 2nd x4540 so even if you would loose
>entire box/data for some reason you would still have a spare copy.
>
>Now compare it to a cost of a library, lto drives, tapes, software +
>licenses, support costs, ...
>
>See more details at
>http://milek.blogspot.com/2009/12/my-presentation-at-losug.html
I've just read your presentation Robert. Interesting stuff.
I've also just done a pen and paper exercise to see how much 30TB of
tape would cost as a comparison to your disk based solution.
Using list prices from Sun's website (and who pays list..?), an SL48
with 2 x LTO3 drives would cost £14000. I couldn't see a price on an
LTO4 equipped SL48 despite the Sun website saying it's a supported
option. Each LTO3 has a native capacity of 300GB and the SL48 can
hold up to 48 tapes in the library (14.4TB native per library). To
match the 30TB in your solution, we'd need two libraries totalling
£28000.
You would also need 100 LTO3 tapes to provide 30TB of native storage.
I recently bought a pack of 20 tapes for £340, so five packs would be
£1700.
So you could provision a tape backup for just under £30000 (~$49000).
In comparison, the cost of one X4540 with ~ 36TB usable storage is UK
list price £30900. I've not factored in backup software since you
could use an open source solution such as Amanda or Bacula.
A more apples to apples comparison would be to compare the storage
only. Both removable drive and tape options require a server with FC
or SCSI ports, so that can be excluded from the comparison.
I think one should actually compare whole solutions - including servers,
fc infrastructure, tape drives, robots, software costs, rack space, ...
Servers like x4540 are ideal for zfs+rsync backup solution - very
compact, good $/GB ratio, enough CPU power for its capacity, allow to
easily scale it horizontally, and it is not too small and not too big.
Then thanks to its compactness they are very easy to administer.
Depending on an anvironment one could deploy them always in paris - one
in one datacenter and 2nd one in other datacanter with ZFS send based
replication of all backups (snapshots). Or one may replicate
(cross-replicate) only selected clients if needed.
--
Robert Milkowski
http://milek.blogspot.com
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