Steve Cousins wrote:
Sevrin Robstad wrote:
I'm suffering from bad performance on my RAID5.
a "echo check >/sys/block/md0/md/sync_action"
gives a speed at only about 5000K/sec , and HIGH load average :
What do you get when you try something like:
time dd if=/dev/zero of=/mount-point/test.dat bs=1024k count=1024
where /mount-point is where /dev/md0 is mounted.
This will create a 1 GiB file and it will tell you how long it takes
to create it. Also, I'd try running Bonnie++ on it to see what the
different performance values are.
I don't know a lot about the md sync process but I remember having my
sync action stuck at a low value at one point and it didn't have
anything to do with the performance of the RAID array in general.
I ran the a couple of times, and got either about 28MB/s or about
34MB/s. strange.
When I run the same test on a single disk connected to another
controller I get about 60MB/s.
[root@compaq ~]# time dd if=/dev/zero of=/mnt/gigaraid/1gb.testfile
bs=1024k cou nt=1024
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 38.1873 seconds, 28.1 MB/s
real 0m38.321s
user 0m0.009s
sys 0m8.602s
[root@compaq ~]# time dd if=/dev/zero of=/mnt/gigaraid/1gb.testfile
bs=1024k cou nt=1024
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 31.4377 seconds, 34.2 MB/s
real 0m31.949s
user 0m0.016s
sys 0m8.988s
[root@compaq ~]# time dd if=/dev/zero of=/mnt/gigaraid/1gb.testfile
bs=1024k cou nt=1024
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 37.599 seconds, 28.6 MB/s
real 0m38.151s
user 0m0.011s
sys 0m9.291s
[root@compaq ~]# time dd if=/dev/zero of=/mnt/gigaraid/1gb.testfile
bs=1024k count=1024
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 31.2569 seconds, 34.4 MB/s
real 0m31.765s
user 0m0.007s
sys 0m8.913s
[root@compaq ~]# time dd if=/dev/zero of=/mnt/gigaraid/1gb.testfile
bs=1024k count=1024
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 37.4778 seconds, 28.7 MB/s
real 0m37.923s
user 0m0.009s
sys 0m9.231s
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