[Gluster-devel] Question about unify over afr

Krishna Srinivas krishna at zresearch.com
Thu Aug 28 05:06:30 UTC 2008

On Wed, Aug 27, 2008 at 10:55 PM, Łukasz Mierzwa <l.mierzwa at grono.net> wrote:
> Tuesday 26 August 2008 16:28:41 Łukasz Mierzwa napisał(a):
>> Hi,
>> I testing glusterfs for small files storage, first I've setup a single disk
>> gluster server, connected to it from another machine and served those files
>> with nginx. That worked ok, I got good performance, on average about +20ms
>> slower for each request but that's ok. Now I've setup unify over afr (2 afr
>> groups with 3 servers each, unify and afr on the client side, namespace dir
>> is on every server, as other stuff afr'ed on the client side), this is
>> mounted on one of those 6 servers. After writing ~200GB files from
>> production server I started to do some tests and I've noticed that doing
>> simple ls on that mount point causes as many writes as reads, this has to
>> do something to either unify or afr, I suspect that those writes are do to
>> namespace but I need to do more debugging. It's very annoying that simple
>> reads are causing so many writes. All my servers are in sync so there
>> should not be any need for sealf-healing. Before I start debugging it I
>> wanted to ask if this is normal? Shoud afr or unify generate so many writes
>> to namespace or maybe xattrs during reads (storage is on ext3 with
>> users_xattrs on)?
> I tested it a little bit today and I found out that if I got 1 or 2 nodes in
> my afr group for namespace there are no writes at all while doing ls, if I add
> one or more nodes they are starting to get writes. WTF?

Do you mean that your NS is getting write() calls when you do "ls"?

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