# NFS with sync result in horrible performance drops.

## dE_logics

I'm doing heavy stuff with NFS, like putting a VirtualBox hard drives (vid) on the share and running the OS installed in it, unsquashing FS etc... and soon I'll be network booting,

During unsquash and with the async options, I get i/o errors after which the unsquashing stops. Lowering the rsize,wsize solves the problem partially (I cant turn it to below 24), i.e. it will fail but after sometime.

The consequence of using sync is it halves the performance, so I'm very keen to use async.

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## dE_logics

No one knows?

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## Hu

Poor NFS performance with sync is expected.  Do not use it unnecessarily.  It sounds like you have two problems.  First, you put some content on the NFS server that ought not be there.  Second, you have some serious network reliability issues if you cannot even move 24 byte NFS packets without experiencing errors.  What kind of transport layer are you using?  Are you doing NFS over UDP or TCP?

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## dE_logics

TCP

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## dE_logics

I had the soft mount option applied, as a result the nfs client implementation dropped requests after they timed out.

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## Hu

Use hard mounts and fix your network not to drop so much traffic.  Failing to transmit packets that are fewer than 32 bytes of application data is a major problem.

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