Date: Tue, 29 Aug 2017 17:11:26 -0500 From: CyberLeo Kitsana <cyberleo@cyberleo.net> To: Kaya Saman <kayasaman@gmail.com>, freebsd-questions@freebsd.org Subject: Re: NFS home directory performance tuning for Linux client Message-ID: <81615b0c-a94c-1fca-de5c-cc8cc868b05c@cyberleo.net> In-Reply-To: <e8e7159f-7ef3-6231-0f86-a7b0e2354340@gmail.com> References: <30d13a2b-0813-9686-3841-b24051fa3e0e@gmail.com> <e8e7159f-7ef3-6231-0f86-a7b0e2354340@gmail.com>
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On 08/21/2017 01:47 PM, Kaya Saman wrote: > So, currently I've tried doing something a little different which worked > out well.<snip> > The bottleneck was definitely caused by NFS and I think it was the write > behaviour for small files, with the limited options available though I > have no idea what could be causing the issues or how to get round them?? Try setting sync=disabled on the zfs datasets backing your NFS shares. If this has a noticeable impact on performance, you may instead want to invest in a SLOG device. This can be a mirrored pair of high-iops/low-latency SSDs, or a battery-backed RAM device. Ordinarily, the ZIL is on the pool's main storage. If you have a bunch of high-latency spinning disks, this can slow sync writes way down as they then have to wait for the disks to finish. An external ZIL on a fast SLOG device will boost sync writes closer to the throughput of the SLOG than the pool. If I remember correctly, all NFS writes are sync writes, and will be impacted by the latency of the ZIL. Setting sync to disabled on a dataset will eliminate the guarantees of sync writes (data loss possible in the case of crash or power loss) but may speed up NFS through this compromise. I would not recommend leaving sync disabled, though. https://www.ixsystems.com/blog/o-slog-not-slog-best-configure-zfs-intent-log/ -- Fuzzy love, -CyberLeo <CyberLeo@CyberLeo.Net> Technical Administrator CyberLeo.Net Webhosting http://www.CyberLeo.Net Element9 Communications http://www.Element9.net Furry Peace! - http://www.fur.com/peace/
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