[lug] Reliable SATA server?

Sat Apr 21 13:42:33 MDT 2012

On Sat, 2012-04-21 at 09:03 -0600, Rob Nagler wrote:
> Over the years we've struggled to find a reliable SATA server for our
> backups.  I have tried numerous versions of SATA computers, and they
> all seem to fail under our loads, always.  The failure is usually in
> the form of the computer hanging in such a bad state that it requires
> a power cycle.

> At this stage, I'm tempted to bite the bullet and go with SAS.  We
> have SCSI3 machines running with heavy (but dissimilar) loads without
> a problem.
> 
> I've asked this question on this list before, and not gotten a
> satisfactory answer.  Nobody seems to run the same type of loads that
> we do, and all their servers run just fine.  However, if you do have
> experience with non-sequential writing of large amounts of data to
> on a SATA server, please let me know. 
> 

Lots of people probably run more demanding work than you, but it's
always hard to understand someone else's one-off project.

Tell us as much as possible about the hardware that is not satisfactory
and more about how it fails.  I'm interested in knowing CPU type,
memory, BUS, card list.  Lots of detail.

# cat /proc/cpuinfo
# cat /proc/meminfo

Tell us more detail about your drive configuration.  # of drives, how
they are configured, raid, filesystem, etc.

The numbers below suggest that at least during this run most of your
activity is read not write..

SAS some advantages over SATA: higher spindle rotation speed of 10K to
15K, and much better internal error handling.  If you're saying your
satisfied with old SCSI drives and SATA has issues, then perhaps SAS
would be a good move.  But right now I think lots more memory might be
the answer.

> # vmstat 1
> procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------
>  r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
>  0  2    144  15672 328852 826992    0    0   300   184    9    3  2  1 91  6  0
>  0  2    144  16136 328436 827052    0    0  3684     0 1544 1361  3  2 55 39  0
>  0  2    144  19764 326164 826964    0    0 10948     0 1270 1253 10  2 52 37  0
>  2  1    144  26640 321224 826268    0    0 27828  2948 1295 2364 21  3 50 26  0
>  0  2    144  26504 320472 827268    0    0  5832     0 1375 1150 10  1 54 35  0
>  0  3    144  29356 319048 826360    0    0  4688   784 1371  984 13  2 52 33  0
>  0  3    144  29232 319048 826528    0    0    32  5624 1114   90  0  0 62 37  0
>  0  2    144  29232 319048 826508    0    0     8   748 1119   72  0  0 54 46  0
>  0  3    144  29232 319052 826532    0    0     8    36 1094   56  0  0 26 74  0
>  0  2    144  29608 318708 826432    0    0  3244     4 1446 1138  3  2 52 43  0
>  0  2    144  29884 318204 826952    0    0  2344  1000 1294  656  2  1 55 42  0
>  1  2    144  32428 316516 826648    0    0  6388     0 1167  732 10  2 49 40  0
>  1  2    144  35916 314220 825756    0    0  7476     0 1205  837 11  2 49 38  0
>  0  2    144  37940 312616 825584    0    0  6484     0 1228  835 10  2 49 40  0
>  0  2    144  39108 311712 825816    0    0  4184 14048 1235  553  5  1 50 44  0
>  0  3    144  39428 310848 826544    0    0  4528  4956 1333  939  6  2 53 40  0
>  0  3    144  39428 310852 826676    0    0     8   784 1131   80  0  0 51 49  0
>  0  2    144  39428 310852 826644    0    0     8   468 1099   78  0  0 50 50  0
>  0  2    144  40328 310620 825876    0    0   912     0 1338  694  0  0 52 48  0
>  0  2    144  39600 310476 826804    0    0  3092   104 1492 1285  1  2 60 37  0
>  0  2    144  40972 309896 826492    0    0  3636  1052 1312  806  3  1 54 42  0

-- 
Maxwell Spangler
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