lkml.org 
[lkml]   [2008]   [Jun]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectLimits of the 965 chipset & 3 PCI-e cards/southbridge? ~774MiB/s peak for read, ~650MiB/s peak for write?
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.


\
 
 \ /
  Last update: 2008-06-01 11:49    [W:0.085 / U:0.344 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site