[ale] ATL Colocation and file server suggestions

Jim Kinney jim.kinney at gmail.com
Mon Jan 19 21:19:46 EST 2009


On Sat, Jan 17, 2009 at 3:43 PM, Ken Ratliff <forsaken at targaryen.us> wrote:

> I do not recommend doing software RAID5 though, get a proper card.

Ditto! Software RAID5 is bad. If RAID5 is required, use a hardware RAID card.

However, software RAID 1, 10 is excellent and performance compatible
with a hardware card.

At a previous job where many, MANY drives were installed in many
<confidential number> machines, it was determined that RAID 5 was a
detriment. 2 failed drives was system death. The recovery time on
large (>500GB) drives was problematic enough that second drive failure
was less than a negligible probability given that all drives were same
make and model. RAID 1 recovery is substantially quicker and drives
are low cost enough to not need the N-1 space of RAID 5. Comparing the
cost of SAS vs. SATA300, it's less expensive to put in an extra
SATA300 in a RAID1 system for an extra spindle to read from and have
more overall storage space. SAS drives are faster total throughput
than SATAII but the cost/performance/lifespan/GB data puts SATAII as a
better choice. 1TB SAS = $250. 1TB SATA=$100. Both have 5 year
warranty and 7200 RPM. SATA has 32 MB cache, SAS has 16 MB. SAS uses
more power and runs hotter (thus more cooling costs).

Until SAS cables make the next leap in performance, SATA is a better deal.

-- 
-- 
James P. Kinney III


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