NAS devices

[Daniel Feenberg]

On Mon, 31 May 2010, Jerry Feldman wrote:

> A while back we had a discussion on NAS devices. It appears that my
> office is expanding. Currently we are using a Linux system with non-RAID
> drives serving both NFS for our 9 Linux systems and a few directories
> exported via SAMBA. That Linux box is a SCSI box that is pretty well
> maxed out. We currently have over 800GB of data. For backup we are using
> a WD Mybook 2TB system which is adequate but very slow. What I am
> looking for is a rack mounted 1U or 2U dedicated system. All but 2 of
> the Linux systems are in the rack. We currently have a 24 port Netgear
> gigabit switch in the rack. For performance I could set up a NAS devices
> on a private network with its own switch connected to the second port of
> the existing servers.
> What we probably will need is initially 2TB usable storage in the RAID1,
> 5 or 6 configuration to replace the current Linux server.

If you are looking for performance, you should think about a RAID 10. Raid 
5 in Linux is problematic, since resonstruction is so unreliable. (See 
http://www.nber.org/sys-admin/linux-nas-raid.html ). Our experience is 
that RAID 0 with two drives is twice as fast as RAID 1, while we haven't 
tried 10, I don't see why it shouldn't do as well. We haven't found any 
other way to improve Linux as a NAS host but would love to learn of one. 
We haven't found that 10,000 rpm drives or 3ware controllers made much of 
a difference for our large seqential access files. Random access may be 
different - you don't say what interests you.

> One system that looks good is the Netgear ReadyNAS series.
>

A homemade server has the advantage that you can update the OS, add 
software such as rsync, and replace the hardware, all without the 
permission of the vendor. I would be very suspicious of the willingness of 
Netgear to allow me to do any of that.

You might think that Netgear support would be valuable, but I would expect 
that should something go wrong with, for example, the motherboard, they 
would ask you to return the entire device for replacement, and your data 
would be gone. Of course you have a backup, but the restore will take 
several days and you will lose the changes since the last backup. If you 
have a homemade system you can buy a replacement MB at Microcenter and be 
up with all your data in a few hours.

Daniel Feenberg

> I would prefer that the systems run Linux internally and support both
> NFS as well as Samba. As I mentioned above, performance is important. I
> don't think that I would need the private LAN option initially. I would
> probably use the higher speed SATA drives. At this point a SAN is
> probably too expensive.
>



> I'm just looking for personal experience with NAS devices so when I make
> a recommendation, I will have some experiences.
>
>
> -- 
> Jerry Feldman <gaf-mNDKBlG2WHs at public.gmane.org>
> Boston Linux and Unix
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