DS4300 Performance Issues

[SirCam]

Hi,

We are running a DS4300 with Netware 6.5 SP5. I have a RAID1 volume with 1 disks mirrored to 1 disk (with a remote mirror of this to a DR SAN) configured. We are experiencing performance issues writing to the SAN. When we write 5.7GB from a SAN volume to the local disk it takes 4mins. When I copy the data back to the SAN it takes 12mins. I would have thought that it would be much faster going TO the SAN because of write cache.

Is there anything I can check or tweak or be aware of with this?

Thanks,

Cam.

 

[mbourne2006]

Hi

You can use the performance monitor in the "Storage Manager Client" software. The icon looks like a little alarm clock to me.

BTW - what sort of remote mirroring? It might be the case that this is the source of your slowness; if the OS does not consider the write to be complete until the remote mirror sends notification ...

HTH

Kind Regards,
Matthew Bourne
"Find a job you love and never do a day's work in your life.

 

[s36e175]

See what performance you get when remote mirroring is turned off.

Write cache is designed to buffer small random writes. If you do sequential writes the cache will flood and will actually slow it down.

I think v9.16 of the Storage Manager code might auto-tune the cache management? but you can also disable write caching on a LUN by LUN basis.

By the way, DS4300 is pretty quick for an entry disk system - I have seen many, and the only real-world application performance problems I have ever seen have been caused by not having enough disk drives allocated for the workload.

Regards.