[Gluster-users] Write performance tragically slow

Pavel Snajdr snajpa at snajpa.net
Mon Nov 15 14:49:13 UTC 2010


I played with it further after I wrote that e-mail and I found out, that 
this interesting thing:

dd if=/dev/zero bs=X count=10000

X	troughput
1k	~3MB/s
2k	~6MB/s
4k	~12MB/s
8k	~24MB/s
16	~48MB/s
...
128k	110MB/s

=> meaning I have tragically low IOPS (+- according to my 0.030ms 
network latency).

Gluster config was one generated by "gluster" command (version 3.1.0), 
but I've tried either latest 3.0.x, resulting the same.

I've tried probably all performance translators available, even AFR 
instead of replicate.

Is there any way to aggregate the writes and propagate them to the 
network in bigger chunks, ie. 128k?

What I don't understand is how for example NFS does this? With NFS there 
is no such problem and even though IOPS are slig

On 15.11.2010 14:22, Luis E. Cerezo wrote:
> have you tried larger files? I have seen a note somewhere that refers to tons of itty bitty files, it even cites the kernel source as an example. I can't seem to find it.
>
> Could you try larger than 1k files?
>
> -luis
>
>
>
>
> On Nov 10, 2010, at 8:23 PM, Pavel Snajdr wrote:
>
>> Hello,
>>
>> I imagine you get this kind of messages all the time, but just in case:
>>
>> I have setup with 2 storage servers with debian package of gluster - version 3.1.0
>>
>> They are connected by dedicated 1 gigabit ethernet cards.
>>
>> I've set up simple replicated storage with 2 replicas and transport over TCP (just followed the how to on the wiki with obvious changes).
>>
>> Here goes my problem:
>>
>> If I try to copy small files (i.e. extract kernel source) I get a horrible results:
>>
>> praha-storage2:/mnt/test# time tar xf linux-2.6.26.8.tar.bz2
>>
>>
>> real 15m19.825s
>> user 0m13.989s
>> sys 0m5.152s
>>
>> likewise when rsyncing OpenVZ VPSes - I just can't get over 2MB/s in syncing.
>>
>> I've monitored all resources - CPU load, network, disk I/O - they are all used up to 0.00000nothing %.
>>
>> Network latency is about 0.11 ms all the time.
>>
>> Is this normal, or am I doing something wrong?
>>
>> Please help. I am frustrated :(
>>
>> --
>> S pozdravem / Best Regards
>>
>> Pavel Šnajdr
>> +420 720 107 791
>>
>> http://vpsfree.cz
>>
>> _______________________________________________
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>> Gluster-users at gluster.org
>> http://gluster.org/cgi-bin/mailman/listinfo/gluster-users
>>
>
> Luis E. Cerezo
>
> blog:     http://www.luiscerezo.org
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> twitter: http://twitter.com/luiscerezo/
> Voice: +1 412 223 7396
>
>



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