[Samba] understanding stat cache

Ralph Boehme
Wed, 15 Nov 2023 16:15:35 -0000

Hi,

On 11/15/23 09:33, Ulrich Sibiller wrote:
> Thanks for that hint about case sensitivity's performance penalty.
>
> For clarifaction: The user is doing mainly reads, so does the
> "create" you mention also cover opening/reading files?

no.

Is it a metadata heave small file workload? That will likely be somewhat
slower compared to Windows, but not in the order of magnitudes.

Otoh there were a few regression in the gpfs module in recent months, so
it might make some sense digging deeper why your workload performs so
bad in this setup.

> If only
> _creation_ of files is suffering from that we probably have some
> other/further performance issue.
>
> We have gpfs, which does not offer a case-insensitive mode, neither
> does the vfs_gpfs module.

the gpfs VFS module actually does support looking up files in a
case-sensitive manner by using gpfs_get_realfilename_path() from libgpfs.

-slow

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