On 10/1/12 4:06 PM, Alan Brown wrote:
> On 01/10/12 23:38, Stephen Thompson wrote:
>>
>> More importantly, I realized that my testing 6 months ago was not on
>> all 4 of my drives, but only 2 of them.  Today, I discovered one of my
>> drives (untested in the past) is getting 1/2 the throughput for random
>> data writes as the others!!
>
> "smartctl -a /dev/sg(drive)" will tell you a lot
>
> Put a cleaning tape in it....
>
>
>
>
>


Cleaning tape did not improve results.

I see some errors in the counter log on the problem drive, but I see 
even more errors on another drive which isn't having a throughput 
problem (specifically SL500 Drive 1 is the lower throughput, but C4 
Drive 1 actually has a higher error count).



SL500 Drive 0 (~60MB/s random data throughput)
=============
Error counter log:
            Errors Corrected by           Total   Correction 
Gigabytes    Total
                ECC          rereads/    errors   algorithm 
processed    uncorrected
            fast | delayed   rewrites  corrected  invocations   [10^9 
bytes]  errors
read:          0        0         0         0          0          0.000 
           0
write:         0        0         0         0          0          0.000 
           0


SL500 Drive 1 (~30MB/s random data throughput)
=============
Error counter log:
            Errors Corrected by           Total   Correction 
Gigabytes    Total
                ECC          rereads/    errors   algorithm 
processed    uncorrected
            fast | delayed   rewrites  corrected  invocations   [10^9 
bytes]  errors
read:          0        0         0         0          0          0.000 
           0
write:     10454        0         0         0     821389          0.000 
           0


C4 Drive 0 (~60MB/s random data throughput)
==========
Error counter log:
            Errors Corrected by           Total   Correction 
Gigabytes    Total
                ECC          rereads/    errors   algorithm 
processed    uncorrected
            fast | delayed   rewrites  corrected  invocations   [10^9 
bytes]  errors
read:          2        0         0         0          2          0.000 
           0
write:         0        0         0         0          0          0.000 
           0


C4 Drive 1 (~60MB/s random data throughput)
==========
Error counter log:
            Errors Corrected by           Total   Correction 
Gigabytes    Total
                ECC          rereads/    errors   algorithm 
processed    uncorrected
            fast | delayed   rewrites  corrected  invocations   [10^9 
bytes]  errors
read:          2        0         0         0          2          0.000 
           0
write:     18961        0         0         0      48261          0.000 
           0




Stephen
-- 
Stephen Thompson               Berkeley Seismological Laboratory
stephen AT seismo.berkeley DOT edu    215 McCone Hall # 4760
404.538.7077 (phone)           University of California, Berkeley
510.643.5811 (fax)             Berkeley, CA 94720-4760

------------------------------------------------------------------------------
Don't let slow site performance ruin your business. Deploy New Relic APM
Deploy New Relic app performance management and know exactly
what is happening inside your Ruby, Python, PHP, Java, and .NET app
Try New Relic at no cost today and get our sweet Data Nerd shirt too!
http://p.sf.net/sfu/newrelic-dev2dev
_______________________________________________
Bacula-users mailing list
Bacula-users AT lists.sourceforge DOT net
https://lists.sourceforge.net/lists/listinfo/bacula-users