Am 23.10.2013 um 17:18 schrieb Les Mikesell <lesmikesell@xxxxxxxxx>:
> On Wed, Oct 23, 2013 at 4:01 AM, Leon Fauster
> <leonfauster@xxxxxxxxxxxxxx> wrote:
>> Am 23.10.2013 um 07:52 schrieb James A. Peltier <jpeltier@xxxxxx>:
>>> | i have a new setup where the htdocs directory for the webserver
>>> | is located on a nfs share. Client has cachefilesd configured.
>>> | Compared to the old setup (htdocs directory is on the local disk)
>>> | the performance is not so gratifying. The disk is "faster" compared
>>> | to the ethernet link but the cache should at least compensate this
>>> | a bit. Do they exist more pitfalls for such configurations?
>>> |
>>>
>>> The best thing to do with respect to NFS shares is to make extensive use of caching
>>> in front of the web servers. This will hide the latencies that the NFS protocol will
>>> bring. You can try to scale NFS through use of channel bonding or pNFS/Gluster but
>>> setting up a reverse proxy or memcached instance is going to be your best bet to making
>>> the system perform well.
>>
>>
>> All web-frontends (multiple) have the filesystem caching already in
>> place (bottom layer). The application uses a key-value-store in memory (top layer) to
>> accelerate the webapp (php). Nevertheless the performance is not satisfying. I was looking
>> at some caching by the httpd daemon (middle layer). Any experiences with such apache
>> cache out there?
>
> What kind of throughput and latency are you talking about here? NFS
> shouldn't add that much overhead to reads compared to disk head
> latency and if you enable client caching might be considerably
> faster. If you are writing over NFS you don't get the same options,
> though and sync mounts are going to be slow.
bonded (just for failover) interface with speed: 1000Mb/s duplex: Full
ping gives me a round-trip echo packet with ~ 0.139 ms
writes ~ 57,9 MB/s (dd test)
reads ~ 59,7 MB/s (uncached), 3,9 GB/s (cached) (dd test)
nfsstat -m output:
rw,nosuid,noexec,relatime,vers=3,rsize=32768,wsize=32768,namlen=255,soft, \
nosharecache,proto=tcp,timeo=20,retrans=4,sec=sys,mountaddr=xxx.xxx.xxx.xxx, \
mountvers=3,mountport=102734,mountproto=tcp,fsc,local_lock=none,addr=xxx.xxx.xxx.xxx
async is implicit. UDP would perform better but we voted for reliability
but even TCP should perform a bit better, i guess :)
the webapp caches also stat calls.
so far
--
LF
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