Re: NAS or USB Backup?
- From: Dave W <mtdave@xxxxxxxxx>
- Date: Mon, 3 Dec 2007 10:54:32 -0800 (PST)
On Nov 30, 10:10 am, "kj [SBS MVP]" <KevinJ....@xxxxxxxxxxxxxxxxxx>
wrote:
Les Connor [SBS MVP] wrote:
Is the point not that disk writes are the bottleneck, and it won't
matter didly whether the network or USB is used?
I was thinking though that the "NAS" might be Raid based with cache and
multi spindle opening that bottleneck some over the single spindle, single
interface USB drive.
I've done network utilization monitoring of standard (NTbackup) backup and
most of the time it's very low in utilization. When backup hits large files
(like the Exchange store) it'll jump right up there, but drops right back
when it backs up those little 1K files. Using a remote agent like Backup
Execs does make a significant improvement but overall Net util overall still
isn't usually over 25%.
"kj [SBS MVP]" <KevinJ....@xxxxxxxxxxxxxxxxxx> wrote in message
news:e4Nik2yMIHA.4688@xxxxxxxxxxxxxxxxxxxxxxx
Dave W wrote:
On Nov 29, 10:26 pm, "kj [SBS MVP]" <KevinJ....@xxxxxxxxxxxxxxxxxx>
wrote:
Dave Nickason [SBS MVP] wrote:
I hate to ask the obvious, but are you sure there are no 100 mb
ethernet devices between the server and the NAS? If there's a
slow switch in the path, that would obviously have an effect.
And not all GigaBit switches are equal. Compare the specs, noteably
the max store - forward rates and make sure the ports are in full.
I've seen a couple of low end 1G switches underperform a decent
100M one. ( I still get better backup performance to the USB
drives than my 'storage server' on the same HP GB switch.)
"Brian Cryer" <bri...@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
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"Dave W" <mtd...@xxxxxxxxx> wrote in message
news:0a502c22-ef3b-4e87-a2f7-bd57ac0601a4@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
I feel stupid asking this question but I keep getting different
answers. Can someone help me figure out which option will
produce a faster backup?
Server has USB 2.0 and a gigabit NIC. Looking at Western
Digital External hard drive solutions
Gigabit 1TB NAS drive or a USB 2.0 1TB connected?
I wouldn't have thought it would make much difference. If you are
copying large amounts of data then you are limited by how fast
you can stream that data to the disk. Both USB and gigabit can
stream data faster than it can be written to the disk so
logically neither of those will be a bottleneck. (I'm not an
expert, but in most cases I would expect USB to outperform NAS,
but there are many factors so there may be cases where NAS would
outperform USB.)
If you want to speed things up then I think you are probably
looking in the wrong place. Consider how much you are backing up,
and whether some of those can be differential backups rather than
full backups. Consider also the read speed of the drives you are
backing up from and the write speed of the drive you are backing
up to.
Given a choice between NAS or USB for backup, my question would
be how often are you cycling the backup off-site and which is
the more convenient to configure, unplug and carry? I use NAS
for providing additional network storage for users but backup to
USB.
Hope this helps.
--
Brian Cryer
www.cryer.co.uk/brian
--
/kj- Hide quoted text -
- Show quoted text -
I appreciate the feedback. If USB 2.0 is 480 Mbps and a gigabit NIC
(with a gigabit switch connected to a gigabit NAS) is running at
1000 Mbps, shouldn't the NAS External Drive outperform? Right now,
our NAS Western Digital is the end point for the full system backup
as per the standard backup process in SBS 2003. Once it hits our
data drive, it is taking 17 hours to complete.
I'm going to double check connections but I can say for sure, we
don't have any 10/100 switches in the mix.
I'm not familiar with max store - forward rates. We are using Dell
Powerconnect 2724 switches if that helps bring anything to light.
Your suggestions and feedback are greatly appreciated.
Thank you.Dell Powerconnect 2724;
Forwarding Rate 35.6 Mpps
HP Procurve 2724;
Forwarding Rate 35.6 Mpps
Looks like a buy-out / knock off with near equal specs.
Anyway, I have a HP2724 so I can make some comparisons, but not a
true NAS.
Usually it's the slowest component of the sub system (bottleneck)
that makes all the difference. Remember those are the 'speeds' at
which data is transferred over the media, not how much data transfer
can be sustained over a long period of time.
The data path times from;
disk to controller to memory to NIC to Net to NIC to memory to
controller to disk
may take substantially more time than;
disk to controller to memory to controller to disk
Isn't benchmarking / baselining fun?
--
/kj
--
/kj- Hide quoted text -
- Show quoted text -
OK, so in theory, a USB 2.0 drive at 480Mbps will run slower than a
gigabit connection runing at 1000Mbps assuming the NIC and the drive
is the same right?
Right now, we are backing up 175GB of data (full backup) to a gigabit
connected Western Digital hard drive -- and it takes 18+ hours. Does
this seem reasonable?
Thanks again for going through the brain damage with me.
.
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