[Samba] vfs readahead && windows server 2016/2019?

[Robert Buck]

Awesome, thanks!



On Mon, Nov 9, 2020 at 8:06 PM Jeremy Allison <jra at samba.org> wrote:

> On Mon, Nov 09, 2020 at 07:26:13PM -0500, Robert Buck wrote:
> > Hi Jeremy, thank you for your very helpful response. We're looking at a
> few
> > more options. Would you have the time to provide some guidance on these,
> > how helpful they may be?
>
> The man pages you're pointing to here are obsolete. All
> accurate information is now in the wiki.
>
> >    - *aio ** ->
> >
> https://www.samba.org/samba/docs/current/man-html/smb.conf.5.html#AIOREADSIZE
>
> Obsolete. All reads/writes should now be done via the pthreadpool. Or
> via io_uring.
>
> >    - *write cache* ->
> >
> https://www.samba.org/samba/docs/current/man-html/smb.conf.5.html#WRITECACHESIZE
>
> Obsolete and code now removed.
>
> >    - *vfs_cacheprime *
> >
> https://www.samba.org/samba/docs/current/man-html/vfs_cacheprime.8.html
>
> Obsolete. Let the kernel do its thing.
>
> >    - *vfs_full_audit*
> >
> https://www.samba.org/samba/docs/current/man-html/vfs_full_audit.8.html
>
> All audit code will slow things down :-).
>
> > If you were to rank the likelihood of these helping, how would you rank
> > them? Are they still applicable in modern Windows and RHEL?
> >
> > Background...
> >
> > Our top challenge right now is Windows Explorer, specifically when you
> get
> > properties on a directory, it takes very long to provide a file count,
> etc,
> > comparatively to a share from another Windows Server.
> >
> > We just moved all CTDB volatile persistent state to NVMe and we have not
> > tested the impact yet, and this may prove significantly beneficial. So
> the
> > Windows Explorer issues may prove to be solved during tomorrow's testing.
> > And we're also planning on testing turning off locking in the root folder
> > this week, as we've been told this can help a lot too.
> >
> > Bear in mind, we are likely to have upwards of 500-800 concurrent users
> per
> > share. We're running in AWS, for both Samba servers and Windows Server
> > (desktop streaming).
>
> The meta-data being fetched on directory read is seems like what
> is causing problems. Funding Samba to add directory leasing code
> will probably help greatly here.
>
>

-- 

BOB BUCK
SENIOR PLATFORM SOFTWARE ENGINEER

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