Subject: Re: [vserver] NFS shares or iSCSI
From: "Michael S. Zick" <mszick@morethan.org>
Date: Sat, 17 Dec 2011 07:22:11 -0600

On Fri December 16 2011, Herbert Poetzl wrote:
> On Mon, Dec 12, 2011 at 03:55:40PM +0100, Eugen Leitl wrote:
> > On Mon, Dec 12, 2011 at 08:22:07AM -0600, Michael S. Zick wrote:
> 
> >> Why not use a small SATA-3 SSD on each of the host machines
> >> as a cache in front of your network file or block system?
> 
> > If I would be running Solaris on my boxes I would do just
> > that (notice that I have only 2 SATA slots on the system,
> > so there's no space for another drive once you go
> > RAID 1). However, as a vserver user, my options are limited
> > to the fs that Linux natively provides. So no SSD caching
> > for me, until btrfs goes production, and actually can deal
> > with SSDs intelligently. 
> 
> hmm ...
> 
> CONFIG_FSCACHE:
> 
> This option enables a generic filesystem caching manager that can be
> used by various network and other filesystems to cache data locally.
> Different sorts of caches can be plugged in, depending on the
> resources available.
> 
> See Documentation/filesystems/caching/fscache.txt for more information.
> 
> Symbol: FSCACHE [=n]
> Type  : tristate
> Prompt: General filesystem local caching manager
>   Defined at fs/fscache/Kconfig:2
>   Location:
>     -> File systems
>       -> Caches
> 
> CONFIG_CACHEFILES:
> 
> This permits use of a mounted filesystem as a cache for other
> filesystems - primarily networking filesystems - thus allowing fast
> local disk to enhance the speed of slower devices.
> 
> See Documentation/filesystems/caching/cachefiles.txt for more
> information.
> 
> Symbol: CACHEFILES [=n]
> Type  : tristate
> Prompt: Filesystem caching on files
>   Defined at fs/cachefiles/Kconfig:2
>   Depends on: FSCACHE [=y] && BLOCK [=y]
>   Location:
>     -> File systems
>       -> Caches
>         -> General filesystem local caching manager (FSCACHE [=y])
> 
> CONFIG_NFS_FSCACHE:
> 
> Say Y here if you want NFS data to be cached locally on disc through
> the general filesystem cache manager
> 
> Symbol: NFS_FSCACHE [=n]
> Type  : boolean
> Prompt: Provide NFS client caching support
>   Defined at fs/nfs/Kconfig:112
>   Depends on: NETWORK_FILESYSTEMS [=y] && (NFS_FS [=y]=m && FSCACHE [=y] || NFS_FS
[=y]=y && FSCACHE [=y]=y)
>   Location:
>     -> File systems
>       -> Network File Systems (NETWORK_FILESYSTEMS [=y])
> 
> not sure what solaris would do 'better' here ...
>

Thank you for looking that up.

I knew it was all in the kernel (somewhere), just did not
have the time to look it up myself.  ;-)

Guess I better bookmark this post so I don't loose the
information (again).

Mike 
> best,
> Herbert
> 
> >> Something like:
> >> http://www.kingston.com/ssd/kc100.asp
> 
> >> Which would (in the 120Gbyte size) run you about $2/Gbyte and
> >> give each client machine a local 90K IOPS cache in front of
> >> your old server network connected at only 1Gbs.
> >> Caching locally about 5% of the network data would greatly
> >> reduce your network load.
> 
> >> Unless you can upgrade your networking to 10Gbs fiber, I think
> >> this would give you about the next best performance.
> 
> >> Mike 
> >>> I think I'll go with an NFS. I have some 3 consumer NAS
> >>> which export NFS as well, and I haven't done iSCSI yet
> >>> so NFS is definitely simpler to deploy.
> 
> 
> > -- 
> > Eugen* Leitl <a href="leitlhttp://leitl.org">leitl</a> http://leitl.org
> > ______________________________________________________________
> > ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org
> > 8B29F6BE: 099D 78BA 2FD3 B014 B08A  7779 75B0 2443 8B29 F6BE
> 
>