[Gluster-devel] Question about unify over afr

[Łukasz Mierzwa]

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?

-- 
Łukasz Mierzwa

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