raid10n2/xfs setup guidance on write-cache/barrier

[Michael Monnerie]

Am Freitag, 16. März 2012, 11:36:07 schrieb Jessie Evangelista:
> If you were in my place with the resource constraints, you'd go with:
> xfs with barriers on top of mdraid10 with device cache ON and setting
> vm/dirty_bytes, vm/dirty_background_bytes, vm/dirty_expire_centisecs,
> vm/dirty_writeback_centisecs to safe values

If you ever experienced a crash where lots of sensible and important 
data were lost, you would not even think about "device cache ON".

> could you please suggest a hardware raid card with BBU that's cheap?

"Cheap" is a varying definition. How much is your data worth? How much 
does one day of blackout cost? 

I've been very happy with Areca Controllers, like the 12x0 and 1680 
series, and now there's the newer 1882 series like 
http://geizhals.at/eu/721745
plus a BBU for about 100€.

You can even mix RAID levels on the same disks, example of 8x1TB define 
a RAID0 of 500G and the rest a RAID6. Online expansion possible, 
scheduled background verify, e-mail notification on everything, logging, 
ntp times, oob-mgmnt via it's own network interface, ...
Very reliable, I never had a problem. And they have a good support team.

-- 
mit freundlichen Grüssen,
Michael Monnerie, Ing. BSc

it-management Internet Services: Protéger
http://proteger.at [gesprochen: Prot-e-schee]
Tel: +43 660 / 415 6531
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