> Right. It's unusual to see this many mount options. FYI, the XFS
> default is relatime, which is nearly identical to noatime. Specifying
> noatime won't gain you anything. Do you really need nosuid, nodev, noexec?
Well better say what I don't want on the filesystem no?
>Do you also see the low write speed and slow ls on md0, any/all of your
> md/RAID10 arrays?
Yes, all drive operations are slow, unfortunately, I have no drives in
that are not managed by the controller to push tests further.
> The usual: "iostat -x -d -m 5" output while the test is running.
> Also, you are using buffered IO, so changing it to use direct IO
> will tell us exactly what the disks are doing when Io is issued.
> blktrace is your friend here....
I've ran the following:
# dd if=/dev/zero of=/srv/store/video/test.zero bs=512K count=6000
6000+0 records in
6000+0 records out
3145728000 bytes (3.1 GB) copied, 179.945 s, 17.5 MB/s
# dd if=/srv/store/video/test.zero of=/dev/null iflag=direct
6144000+0 records in
6144000+0 records out
3145728000 bytes (3.1 GB) copied, 984.317 s, 3.2 MB/s
Traces are huge for the read test so I put them on Google Drive + SHA1 sums:
Drives `sdc` to `sdf` are part of the RAID10 array. Only drives `sdc` and `sde`
are used when reading.
> That makes me wonder if the controller and drive write caches have been
> That could explain this.
Caching is enabled for the controller but not much information.
> sys info
The System Information
Main Processor : 500MHz
CPU ICache Size : 32KB
CPU DCache Size : 32KB
CPU SCache Size : 0KB
System Memory : 128MB/333MHz/ECC
Firmware Version : V1.49 2010-12-02
BOOT ROM Version : V1.49 2010-12-02
Serial Number : Y611CAABAR200126
Controller Name : ARC-1120
By the way is enabling the controller cache a good idea? I would disable
it and let the kernel manage.