[OpenAFS] Client Cache Question

[Jeffrey Altman]

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Timothy,

When asking questions it is helpful if you could specify the
AFS client and server versions involved and the operating systems.

Jeffrey Altman


On 6/21/2013 7:26 PM, Timothy Balcer wrote:
> I have a tiny head scratcher...
>=20
> Tested this case:
>=20
> rsync 100 or so files every 5-10 minutes to an AFS volume which is
> remote over a 100Mbit dedicated WAN (33ms ping times)
>=20
> with cache size =3D 500,000
> with chunksize =3D 19
> rsync -qau -timeout=3D60 --contimeout=3D30 <blah blah>
>=20
> first rsync after afs client restart shows 0.15 - 0.25 seconds to compl=
ete
>=20
> second, and subsequent rsync shows in excess of 30 seconds. It never
> recovers to below one second.
>=20
> Tested some parms... Decreasing cache size to 50,000 AND decreasing
> chunksize to 13 gives consistent performance below 0.3 seconds
>=20
> Increase cache size to 500m with chunksize 13 and the same behavior
> occurs as before.
>=20
> This seems counter intuitive... the 100 or so files do not go over the
> 500,000 block cache size. They are fairly small (10's to 100's of
> kilobytes). Why would increasing cache size impact performance
> Negatively in such a case?
>=20
>=20
> --=20
> Timothy Balcer / IT Services
> Telmate / San Francisco, CA
> Direct / (415) 300-4313
> Customer Service / (800) 205-5510


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