[clug] Managing NAS units?

[Michael Cohen]

In my experience NAS are useful for storing non performance critical
files or basically backups. I know of a place who bought a massive NAS
to store some very large files and then attempted to processes the data
directly off the NAS. Needless to say the performance was so appalling
that it was a total waste of time. In the end they ended up buying a
bunch of local disks and copied the data to them to process locally. I
mean it makes perfect sense - even on gbit ethernet you have so much
overhead with network congestion/locking etc that its just not a good
solution - but people are still very attracted to the whole NAS concept
for some reason. Put your eggs in the one basket type of mentality.
Performance is particularly bad if files are shared over SMB as opposed
to say NFS due to the more complex protocol and much more rigorous
locking behaviour.

NAS are good for storing things like a corporate file server or some
backups (lots of rarely accessed small files - with very low performance
requirements). Especially if the data needs to be available to many
systems at once. Its generally not worth it for mere storage
requirements. In the past there was some economy of scale with NAS
setups but these days its just not worth it - you can stock up each
server with a couple TB of storage cheaply and have reliable seperate
storage for each system.

Michael.

On Thu, Nov 01, 2007 at 07:12:43PM -0700, Michael Still wrote:
> Robert Edwards wrote:
> 
> [snip]
> 
> > My question is: why did those quite independent services need to
> > share the NAS? Why couldn't they each have a smaller NAS for primary
> > storage and possibly share a separate storage system for secondary
> > (backup) storage?
> 
> Yeah, I agree with that. There are other problems with having one mega
> filesystem:
> 
>  - fscks
>  - outages in one NAS take away all
>  - inconsistent disk access speed (one NAS is slower than others for
> some reason)
>  - others I am too lazy to think of
> 
> The approach I've been taking at home recently is to buy commodity PCs,
> stuff them full of disk, and then expose that disk via NFS. There is
> then one file system with a bunch of symlinks mounted everywhere. I
> guess I'm hoping (but haven't tested yet) that Linux is smart enough to
> follow the symlink locally and not push traffic through the server that
> exports that top level file system.
> 
> (Oh, and that's a bit of a lie. I only have two of these machines so
> far, so it's not like I have a data center in my apartment or anything...)
> 
> Mikal
> -- 
> linux mailing list
> linux at lists.samba.org
> https://lists.samba.org/mailman/listinfo/linux