Solved: CIFS performance struggling - Page 2

evilclivemott · ‎2020-06-07

We've got an ageing IBM N6250, aka FAS3250 I think, running 7-Mode 8.2.1

We want to extract a lot of data from this filer using CIFS - we've got 200T+ in about 44 shares on a two headed controller.

Our problem is that the file copies just aren't going fast enough. Individually they work fine, and if I set off a copying job, it works well for a while. But it will then collapse - the transfers simply sit there waiting, being very slow indeed. 15 seconds to shift a 40K file.

The copying job is in powershell on a Win2016 VM, doing CopyItem \\filer\share\file destination. There is 10GbE between the filer and the VM.

What sort of things can cause that? I realise this is a vague question, so please ask me for further information and I'll try and supply it.

cheers,

clive

evilclivemott · ‎2020-06-19

Hi -

Well, we have an answer 🙂

It was the networking after all. The pair of network links are IP balanced, and clearly the snapmirror must have been doing down the other one, hence my previous diagnosis was incorrect.

No networking errors shown on the netapp side, however when we got access to the switches, one of the ports was showing a lot of CRC errors.

Last night we got the offending port turned off, so all the traffic is now going down a single path, and performance is now up to 100%.

Obviously we're doing to get the hardware looked at - we expect that one of the SFPs or the fibre between them needs replacing, and that's under way, because we do want our resilience 🙂

So there's the answer : CIFS performance problems, worth checking the network, including at the switch end, because the underlying network problems won't show on the netapp itself.

cheers,

clive

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