NAS devices

[Jerry Feldman]

On 05/31/2010 11:37 AM, Dan Ritter wrote:

> Not exactly what you asked for, but -- I think very highly of
> the HP P800 SAS/SATA card. You can get a 1U box with four 3.5"
> drives -- don't buy HP drives, the price is astoundingly high --
> and later plug in a 2U 12x3.5" chassis or a 2U 25x2.5" chassis.
> These can be cascaded, too -- 96 3.5" disks (up to 2TB SATA) or
> 50 2.5" disks (500GB SATA or 300GB SAS) depending on whether you
> need more speed or space.
>
> Alternatively, any decent 4 disk 1U box can do 4TB (usable) in
> RAID10 for you.
>
> IMHO, small NAS appliances are primarily for people who can't be
> bothered to set up things that you've already set up.

On 05/31/2010 11:42 AM, Daniel Feenberg wrote:
 >
 > 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.

 >
 > 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.

On 05/31/2010 01:26 PM, Richard Pieri wrote:
 > Based on recent experience with disk failures, I've had very good 
luck with 3Ware RAID controllers in RAID 1 and RAID 5 configurations in 
Linux file and Xen servers.
 >

Thanks for the responses. A couple of other things:
Adding the SATA card is a possibility. All my other servers in the rack 
are SCSI system (Intel Whitebox, but they have onboard SATA controllers 
and I have 1 box rigged and I could upgrade it with a SATA backplane).

I just want to add that our products are very memory intensive. I think 
the HP P800 SAS/SATA card could be useful. Additionally, I need to check 
the performance differences. The best performance would be a RAID0 that 
has striping and no mirroring. I'm very wary of RAID5 since we've been 
burnt on this.

One consideration is that I have 2 unused IA64 boxes that I could use as 
a dedicated NFS server. I didn't think of this earlier. Our products 
currently don't support IA64 as it's architecture is too slow (we spent 
a year at HP porting and benchmarking). One is an HP the other is an 
Intel whitebox.



-- 
Jerry Feldman <gaf-mNDKBlG2WHs at public.gmane.org>
Boston Linux and Unix
PGP key id: 537C5846
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