Dan Foster wrote:

Hot Diggety! Patrick Boutilier was rumored to have written:

We pay only about $8000 CDN for 2TB of RAID5 storage.

Hmm, what disk subsystem and model, if I might ask? We're looking at
two products - the Nexsan ATAboy2 and an equivalent one from Jetstor;
both are pretty much technically identical in all respects and costs
about USD $13,000, and looks great. But that's for a 1.6 TB setup (8x200)
with max usable about 1.2 TB in a RAID-5 + 1 hot spare setup.

Now I'm curious what exceeds that in usable capacity for much cheaper.

We build our own systems using WD 200G drives and 12 port 3ware cards.

Hard drives ~ $400 each
Case and power supply(s) ~ $1000
12 port 3ware card ~ $1000
Motherboard, CPU, RAM ~ $500

Tape solutions are easier and proably cheaper to scale, and since you'll
probably net a library adn drives anyways to handle the copy-storage pool,
you'll probably find that for larger environments, having primairy copies
on
tape does make sense.

Except when you need to restore. Restore from disk is much faster than
restore from tape. :-)

That depends on what type of tape library you have and how you've
configured TSM (such as setting up a separate stgpool just to hold the
directory information, for instance). For example, a LTO-2 drive can
read/write data at up to 35 MB/sec natively, and even more in compressed
mode. That usually gives it a pretty good run compared to RAID-5 disks :)
I usually see about 18-22 MB/sec with RAID-5 drawers from various vendors
and with various hardware-accelerated cache-based RAID controllers.

Also depends on how many tapes need to be mounted. It is pretty nice
when you only need to restore a couple of files and don't have to wait
for tapes to mount.

-Dan

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