[OpenAFS] Server disk operations speed
Sun, 7 Apr 2013 21:55:41 +0300 (EEST)
back on my computer.
So, I thought that the network communication was the bottle neck, but just
in case I tested whether it's the server itself that was somehow
exceptionally slow. I copy/pasted the earlier mentioned test directory
(see the full message below) first in the normal unix environment
/home/user/...(source and target), which turned out to be extremely fast
(HW supported virtualization on a SSD disk). So, no problem there.
Then I got access to an afs account on the same machine (kinit; aklog),
and copied the same test directory in /afs/cell/user/...(source and
target) which turned out to be extremely slow.
All this took place on the very same server machine, without any external
clients. I do suspect that in afs case, some traffic _may_ leave the
machine (use dns to find the external address and return back to the very
same machine, maybe...), which may explain partly the results.
I'm a bit puzzled since everything works, but annoyingly slowly for
serious use. Of course my main concern is the speed for clients, not
within the server.
I did try to optimize the fileserver parameters, but I could only gain
like 30-40% improvement. I believe there is some bigger issue to be solved
first. I wonder if anybody else has had a similar issue, or if you could
think of any possible causes for this sort of symptons?
As said, I'd be happy to give more information.
> Terve Atro,
> I'm willing to give as much information as needed. What kind of
> information you had in mind?
> br, jukka
> Sent from my iPhone
> On 7.4.2013, at 18.47, Atro Tossavainen <email@example.com>
>>> How I tested:
>>> I duplicated the directory A) inside afs space
>>> B) outside afs, but on the same server
>> You'll need to be more precise than that for anybody to be able to say
>> anything, I think.
>> OpenAFS-info mailing list
> OpenAFS-info mailing list
there must be something seriously wrong about my openafs server.
It is still in a development state, so all server functions are located on
a single virtual machine. While trying to figure out optimal fileserver
parameters, I noticed that even the basic disk operations are extremely
slow on the afs server locally.
How I tested:
I had a directory containing about 2000 files, 300 MB in total.
I duplicated the directory A) inside afs space
B) outside afs, but on the same server
While the A) speed was between 500-1000KB/s, for B) the total operation
took only about 2-3 seconds (~150MB/s)!
So, eventhough everything works, there must be some misconfiguration
somewhere, rather than just a parameter optimization. I don't know whether
the traffic leaves the server just to come back immediately, but even then
I would expect faster operations (110/10Mb internet).
The server runs on Ubuntu 10.04, openafs 1.4 or 1.6 made no significant
difference. There is a whole lot of other functionality on the server, so
a total reinstallation is not a pleasent option.
Any ideas what could cause this?
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