Re: Very slow LVM performance
Arcady Genkin put forth on 7/12/2010 10:49 PM:
<very interesting and thorough background snipped for brevity>
> After dealing with all the idiosyncrasies of iSCSI and software RAID
> under Linux I am a bit skeptical whether what we are building is going
> to actually be better than a black-box fiber-attached RAID solution,
> but it surely is cheaper and more expandable.
I share your skepticism. Cheaper in initial acquisition cost, yes, but maybe
not long term reliability and serviceability. Have you performed manual
catastrophic iSCSI target node failure tests yet, monitored the
node/disk/array reconstruction process to verify it all works as expected
without user interruption? This is always the main concern with homegrown
storage systems of this nature, and where "black box" solutions typically
prove themselves more cost effective (at least in user good will $$) than home
brew solutions.
I myself am a fan of Nexsan storage arrays. They offer some of the least
expensive and most feature rich and performant FC and iSCSI arrays on the
market. Given what you've built, it would appear the SATABeast would fit your
needs. 42 SATA drives in a 4U chassis, dual controllers with 4 x 4Gb FC ports
and 4 x 1GbE iSCSI ports, 600MB/s sustained per controller, 1.2GB/s with both
controllers, up to 4GB read/write battery backed cache per controller, web
management/snmp/email alerts via mngt 10/100 ethernet port, etc, etc. The web
management interface is particularly nice making it almost too easy to
configure and manage arrays and LUN assignments.
http://www.nexsan.com/satabeast.php
One of these will run somewhere between $20-40k depending on disk qty/size/rpm
and whether you want/need both controllers. They also offer an SAS version
with 15krpm drives at higher cost. I've installed a couple of the single
controller SATABeast models and the discontinued SATABlade model. They've
performed flawlessly, no drive failures to date. Last I checked Nexsan still
uses only Hitachi (formerly IBM) UltraStar drives.
Good product/solution all around. If you end up in the market for a "black
box" storage solution after all, I'd recommend you start your search with
Nexsan. I'm not selling here, just a very happy customer.
--
Stan
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