[ale] They say drives fail in pairs...

[Jim Kinney]

Jim's RULE of RAID: NEVER, EVER INSTALL RAID DRIVES WITH SEQUENTIAL SERIAL
NUMBERS!!!

If possible, avoid RAID drive purchases from the same supplier and
manufacturer.

I was bit once by a RAID5 failure. The lesson I learned is to image ALL
remaining drives before replacing the failed drive.

Google did research on drive failure rates and recover times and found that
once a drive is larger than 500GB, a RAID5 system is a bad idea. The
failure rate of similar age drives (even mixed version, model, etc.) was
such that the array was likely to fail a second drive before the first
failure had been recovered from. RAID6 only buys a bit more time as it
requires a 3 drive failure for data loss. Based on that and my own
experience, RAID 10 is the only stuff I use now. When the data ABSOLUTELY
must be available, I use a 3 drive mirror spread across 3 different
controllers (so, yes, software raid) so typically, the mobo controller and
2 additional cards. 12 drives in 4 stripes with 3 copies of each stripe
makes me happy. It's an especially good setup for write seldom, read often
servers. The write speed is not sufficient for high-write-throughput
database stuff so I'd incorporate some SSD hardware for WAL stuff.

On Tue, Jan 3, 2012 at 10:59 AM, Michael Trausch <mike at trausch.us> wrote:

> Well, all I am going to say is thank goodness I'm using RAID 6 and not
> RAID 5, or all would have been lost for me at the start of the year.
>
> I'll write more later, I learned that the Linux kernel is also not as
> great in handling certain things as it could be.  :-/
>
>        --- Mike
>
> --
> A man who reasons deliberately, manages it better after studying Logic
> than he could before, if he is sincere about it and has common sense.
>                                   --- Carveth Read, “Logic”
>
>
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-- 
-- 
James P. Kinney III

As long as the general population is passive, apathetic, diverted to
consumerism or hatred of the vulnerable, then the powerful can do as they
please, and those who survive will be left to contemplate the outcome.
- *2011 Noam Chomsky

http://heretothereideas.blogspot.com/
*
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