[OpenAFS] 1.3.x memcache performance

[Andrej Filipcic]

On Monday 27 December 2004 16:50, Horst Birthelmer wrote:
> On Dec 27, 2004, at 3:48 PM, Andrej Filipcic wrote:
> > Hi,
> >
> > I have checked diskcache/memcache performance over an ADSL link.
> > The link has 4M download and 512k upload bandwidth. Although there are
> > still
> > problems with disk cache, the copy from afs to local disk is good
> > enough.
> > With disk cache the speed is ~400 kbyte/s (tcp speed is 500 kbyte/s).
> > Memcahe speed is much lower, between 120 and 160 kbyte/s, depending on
> > the
> > fileserver. Is there any reason (bug) for such a big difference?
> >
> > On gigabit network, the copy speed with memcache is never larger than
> > 20
> > mbyte/s, with disk cache it can go up to 70 mbyte/s.
>
> Can you provide more information on your measuring and test environment?
> I suppose you didn't actually measured AFS performance when you got 70
> MB/s with diskcache. That's pretty unlikely.
>
> Horst

Well, it is not actually performance. dd if=/dev/zero to afs space transfer  
reaches something like that. This is of course a peak number. Half of time 
data is written to a local disk cache with no network activity, so on 
average, the transfer would be 30-40 MB/s. AFS read speed is between 10-20 
MB/s. 

New memcache parameters give similar write transfer now (~60 MB/s on average).

Cheers,
Andrej

-- 
_____________________________________________________________
   doc. dr. Andrej Filipcic,   E-mail: Andrej.Filipcic@ijs.si
   Department of Experimental High Energy Physics - F9
   Jozef Stefan Institute, Jamova 39, P.o.Box 3000
   SI-1001 Ljubljana, Slovenia
   Tel.: +386-1-477-3674    Fax: +386-1-425-7074
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