[Gluster-users] very bad performance on small files

[Edward Capriolo]

On Mon, Jan 17, 2011 at 4:32 AM, Anand Avati <anand.avati at gmail.com> wrote:
> On Sun, Jan 16, 2011 at 5:02 PM, Max Ivanov <ivanov.maxim at gmail.com> wrote:
>
>> >> > time tar cf - M | pv > /dev/null 15.8 MB/sec (native) 3.48MB/sec
>> >> > (FUSE) 254 Kb/sec (NFS)
>> >>
>> >
>> > This test shows why glusterfs native protocol is better than NFS when you
>> > need to scale out storage. Even with a context switch overhead on the
>> client
>> > side, glusterfs scores better due to the "clustered nature" of its
>> protocol.
>> > NFS has to undergo a second hop when it has to fetch data not available
>> in
>> > the server it has mounted from whereas for glusterfs it is always a
>> single
>> > hop to any server it wants to get data from.
>>
>> My tests was done on 2 bircks setup mounted in replica mode, thereby
>> all needed data was avaiable on NFS node and there was no need to do
>> additional hop.
>>
>>
> NFS still undergoes the second hop to complete lookups, verify sanity of
> copies etc. The fops are - lookup(), open(), release().
>
> Avati
>
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>

It is also important to note that many on disk file systems such as
FreeBSD's default file system do synchronous meta operations by
default.

Thus extracting http tar can take 30 seconds while a standard linux
ext3 "seems" to almost extract this file instantly.

So even some non-networked file systems are not fast at extracting large tars.