Re: [opensuse] wait times excessive high {Suse 10.3 & 11}

Sandy Drobic wrote:

Per Jessen wrote:
Greg Freemyer wrote:

Since 1MB was faster than 1GB for some reason, I would try the 4k
one just out of curiosity, but you're likely right it is far slower..


It wasn't that bad - using bs=4k, the file copy was done in 31minutes
at 11.5Mb/sec (dd's transfer-rate).

That's still pretty miserable compared to the power of the other
server components. A cheap sata raid5 on a 3ware controller is already
a step up.

This is a raid5 with 5 sata disks (system with 8 GB RAM):

dd if=/dev/zero of=/tmp/testfile bs=1024k count=20480
20480+0 records in
20480+0 records out
21474836480 bytes (21 GB) copied, 262.764 s, 81.7 MB/s

Yep, very impressive. To be honest, I had also expected more throughput
on my system (RAID1 on 2 SATA drives). In pure write speed I get
29Mb/s - your 3ware controller must be helping a lot here.
Interestingly, I got 33Mb/s on an older PC with a plain PATA drive ... I
guess RAID1 does have its price.

dd if=/tmp/testfile of=/dev/null bs=1024k
20480+0 records in
20480+0 records out
21474836480 bytes (21 GB) copied, 71.9161 s, 299 MB/s

How did you manage that? 300Mb/s read speed??? I tried the same and
got 47Mb/s. Is that the 3ware controller again?

dd if=/tmp/testfile of=/tmp/testfile2 bs=1024k
20480+0 records in
20480+0 records out
21474836480 bytes (21 GB) copied, 636.322 s, 33.7 MB/s

The sad fact is that hdd speed, especially access time has not evolved
with the same speed as other parts of pc hardware.

The operator bus, the memory bus and the peripheral ditto are also way
behind the CPU, but that is the way it has always been.



--
/Per Jessen, Zürich

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