>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.
Which isn't to say tape would be a "better" solution since it's going to be
slower to restore etc. But it does show that tape can work out cheaper,
especially since the cost of a high speed WAN link isn't required.
JR
_______________________________________________
zfs-discuss mailing list
zfs-discuss@opensolaris.org
http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
