Re: [SOLVED] Is squeeze compatible with WD20EARS and other 2TB drives?
Klistvud put forth on 12/19/2010 3:10 AM:
> Dne, 19. 12. 2010 05:31:37 je Stan Hoeppner napisal(a):
>>
>> What is the result of?
>>
>> dd if=/dev/zero of=/some/filesystem/test count=100000 bs=8192
>>
>> That will write an 810MB file of all zeros, and will give you a much
>> better idea of the raw streaming write performance vs copying files from
>> the old 160GB drive to the new one. I would think the result should be
>> a bit higher than 60MB/s.
>>
>> Also, make sure you're using the deadline elevator instead of CFQ as it
>> yields better performance, especially on SATA systems that don't support
>> NCQ:
>>
>> $ echo deadline > /sys/block/sda/queue/scheduler
>>
>> You may want to add this to your boot scripts to make it permanent. I
>> roll this option as the default in my custom kernels.
>>
>
> Thanks for the suggestion, Stan. Using dd I get a much higher figure,
> namely around 83 MB/s. Changing the elevator doesn't make a difference
> on my system though.
83 MB/s isn't too bad for that drive. IIRC the WD20EARS is a 5400 RPM
drive with variable spindle speed to reduce power consumption. My 7200
RPM WD Blue 500GB WD5000AAKS single platter drive hits about the same dd
sequential write speed, using lower bit density but higher spindle speed:
/$ dd if=/dev/zero of=./test count=100000 bs=8192
100000+0 records in
100000+0 records out
819200000 bytes (819 MB) copied, 9.8092 s, 83.5 MB/s
The deadline elevator may not help much with streaming reads/writes. It
does help a bit with random read/writes, especially under multi-user or
multi-threading random seek disk workloads.
--
Stan
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