Re: [vserver] NFS shares or iSCSI

From: Herbert Poetzl <herbert_at_13thfloor.at>
Date: Sat 17 Dec 2011 - 01:19:31 GMT
Message-ID: <20111217011931.GD25290@MAIL.13thfloor.at>

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 ...

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 leitl http://leitl.org
> ______________________________________________________________
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Received on Sat Dec 17 01:19:47 2011

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