I have 12 enterprise-class seagate 1TiB disks on a 965 desktop board and
it appears I have hit the limit, if I were able to get the maximum speed
of all drives, ~70MiB/avg * 12 = 840MiB/s but it seems to stop aound 774
MiB/s (currently running badblocks on all drives)..
I am testing some drives for someone and was curious to see how far one
can push the disks/backplane to their theoretical limit.
dstat output:
----total-cpu-usage---- -dsk/total- -net/total- ---paging-- ---system--
usr sys idl wai hiq siq| read writ| recv send| in out | int csw
1 12 0 83 3 2| - 0 | 0 0 | 0 0 | 13k 23k
1 11 0 84 2 2| 774M 0 |2100B 7373B| 0 0 | 13k 23k
1 12 0 83 3 2| 774M 0 | 0 0 | 0 0 | 13k 23k
1 11 0 82 4 2| 774M 0 |2030B 5178B| 0 0 | 13k 23k
1 11 0 83 4 2| 774M 0 | 0 0 | 0 0 | 13k 23k
1 11 0 83 3 2| 774M 0 |2264B 6225B| 0 0 | 13k 23k
vmstat 1 output:
~$ vmstat 1
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy id wa
0 12 124 3841772 8 13012 0 0 12595 163880 379 352 0 31 37 32
2 12 124 3841772 8 12992 0 0 791744 8 12796 23033 1 18 0 82
0 12 124 3841772 8 12992 0 0 792192 0 12677 22918 1 15 0 84
0 12 124 3841772 8 12992 0 0 792960 0 12894 22929 1 15 0 84
When I was writing to all of the drives it was maxing out around ~650
MiB/s.
I also have 2 raptors on a PCI card (as I ran out of PCI-e cards) and:
When I read from 1 of the raptors (w/ dd/example shown below) the speed
drops:
1 13 0 79 5 3| 764M 0 |2240B 7105B| 0 0 | 12k 21k
1 13 0 80 5 2| 764M 0 | 0 0 | 0 0 | 12k 21k
1 11 0 82 5 2| 764M 0 |2170B 5446B| 0 0 | 12k 21k
1 12 0 81 5 2| 762M 0 | 0 0 | 0 0 | 12k 21k
Does/has anyone done this with server intel board/would greater speeds be
achievable?
Also, how does AMD fair in this regard? Has anyone run similar tests?
For instance if you have 12 disks in your host you could:
dd if=/dev/disk1 of=/dev/null bs=1M
dd if=/dev/disk2 of=/dev/null bs=1M
What rate(s) do you get?
Justin.
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