Performance of NFS NAS compared to direct SCSI using same disk/controler

[xAyiDe]

Anyone here that can give some thought about performance differencies in the following scenario.

VMFS directly on a local 15k scsi with U320 controller

compared to

VMFS on an NFS share which runs the same 15k scsi with the same u320 controller

I mean will there be a huge difference?

[oreeh]

yes - since there's overhead from the NFS protocol, IP stacks, ...

[xAyiDe]

yeah I guessed some. But will it still be fast than moving to cheapo IDE local storage with supported IDEraid and SCSIdrivers?

[oreeh]

Local storage should be faster - but not as flexible!

[Rumple]

Alot depends on the number of disks as well.

As for using IDERAID I am guessing you are talking for a test environment using the SATA workarounds like the Dell 2610SA or megaraid controllers.

SCSI will def be faster then IDE but more expensive and less capacity.

I have a Test system built with a megaraid SCSI controller with Write cache enabled and battery backup along with a dell 2610sa card.

SCSI - 2x146GB Drives RAID1

SATA 4x250GB 7200RMP drives RAID 5 (and tried RAID10)

SCSI takes 57sec to write out 1GB file

SATA takes 4.5 Minutes for 2GB file creation

SCSI with no write cache was 22 minutes.

[xAyiDe]

That finalizies it. I go for an u320 15k-disk on NFS share instead of local IDE

[Rumple]

but you also have to take into account that nfs has alot of other overhead which may negate the differences in disk access times.

Maybe someone eho's used NFS will see this thread and respond.

[xAyiDe]

yeah thats what I would hope to.