Poor NAS8000 performance with large files

[Saulius_1]

Hi,

I've tried to copy large files into NFS share from local disk. After copying ~160mb, performance decreases dramatically. I mean when I copy 2Gb file, after transferring ~160-200mb, network activity decreases at least twice. Any cache/file size limits ? Or it is famous Linux NFS bug ?

Has someone seen such "feature" ?

Saulius
P.S. Pushing machine is OK, SUN Fire 280R, with free cpu, ant ~1GB of free ram. Disks performance is about 35mb/s, so it should be more than enough for NAS.

[Eugeny Brychkov]

VA large writes are going to RAID5 directly, so a little perfomance decrease may occur. But not dramatic :o(
35-45mb/s for VA is good in average. I saw tests were done showing 45-50mb/s on hpux machines (again, in average).
If it's possible you can check NAS disk subsystem by copying this large file locally, excluding LAN transfers. If it will show good results, the LAN or its software/patches may be the cause, if result will be the same as before then OS patching and storage system is under suspicion.
Try patching NAS8000. I remember on the first release it had 1.4.0 version, but last time I visited HP NAS site there were patches to upgrade it to 1.4.2. I remember there's 1.5 version... I guess you'll find right software to patch with :o)
Good luck!
Eugeny

[Vincent Fleming]

I have a customer who's performance testing a new NAS8000 (v1.5.0), and we're seeing around 40 to 50 mb/s sustained write rate over about 4GB of data.

Perhaps your disk configuraiton is not optimal? Are you using a VA? What model? How is it configured?