NAS file access slow?

The wonders of technology never cease to amaze

However, that massive amount of storage at that price must involve some trade-offs and based on the user comment from the eBuyer site it seems that performance is the obvious candidate:

(from your link) “Despite copying over a 1Gbit network, I was only getting transfer speeds of around 3MB/s”

Further, if you are running 6 windows machines in a small (peer to peer?) network there is going to be a lot of low level network chatter that may be overloading the undoubtedly limited processing power of the drive unit.

I would try disconnecting 5 of the 6 machines from the network to see whether that improves performance towards the 3 Mb/s transfer rate obtained by the eBuyer poster. If that works out you will need something with much more oomph to get acceptable performance.

The typical cheap NAS uses a fairly low power CPU running Linux. 3MB/s is quite typical They are underpowered for 1000Mbps networks
You've got to throw some serious money to get something that'll begin to make use of that bandwidth.

In fact, it's probably faster using a USB2 drive and sharing it through one of the PCs Cheaper too!!

Matt

That will be due to some bottleneck in the system rather than anything to do with the disk drive itself.

The massive amount of storage is achieved by having extra platters, and high capacity platters. Platters can be up to 320 GB now. These provide very high transfer rates.

The price is low because prices of all sizes of drives has come down with advancing technology. You can get a very high quality 320 GB drive for £36, for example.

Maybe so but all other things being equal a smaller disk must be faster than a larger disk, due to the need for the read/write heads to traverse more physical and logical disk divisions.

Further, the high capacity disks I have seen have all been 7,200 rpm which must be a significant performance factor versus the smaller 10,000/15,000rpm disks.

Anyway, one thought occurred to me on this subject; I have a matched pair of 160Gb 10,000 rpm drives configured in a Raid 0 stripe on my main desktop. Does anybody know whether it is possible to add a 3rd disk in a redundant RAID configuration? And if so would that in any way have performance implications? Would appreciate any advice.

It is possible to have a RAID 5 set with three disks but you won't be able to add one to your existing RAID set, so you would need to backup all your data - reconfigure your RAID set with three disks and then restore the data. Once you've created your RAID 5 set it is usually possible to add additional disks without breaking / rebuilding the whole RAID set (as long as your hardware / software supports it).

I'm making the assumption that you're not using Windows software RAID!

You would still only have 320Gb worth of space available with this as the remaining disk space is used for the parity bit.

RAID 5 is (generally) slower at writing but quicker at reading from the disk compared to a RAID 0 configuration - but with a fast RAID controller you wouldn't actually notice this. RAID 0 has the fastest performance.

This is a reasonable summary

Personally I would rather spend the money on an additional 320Gb+ external drive and just backup everything to that.

The higher the areal density (the more gigs per platter), generally, the higher the transfer rate. Random acess times can be slower, though. So they can be faster for copying big blocks of data, but slower for darting about to access small files scattered all over the disc.

Some extra time may be added for dealing with multiple platters, but only a tiny amount, I think. It's not always the case at all anyway. Aparently WD deliberately slowed down their 320 GB single-platter drive to make it quieter. Their 640 GB disc that uses two of the same platters is actually faster.

But the 10,000+ rpm disks are speciality items that cost a lot more. They're getting bigger as well anyway. The new Veloraptor is 300 GB and claims to be the fastest drive available.

Your 10,000 rpm drives may not even be as fast as up-to-date high-capacity 7200 rpm dives if they are a few years old. Find tests and comparisons on the net.

I think it's possible with the Intel system I have on my DELL motherboard. It allows a multiple array with a combination of RAID 0 and RAID 1. I don't know what performance would be like using three discs in an array. I guess good in some ways and not good in others!

Narrowing it down, it's definately an XP problem.

Just accessed via Vista, and icons load almost instantly instead of waiting minutes, operations are performed when I ask it to do them, rather than waiting for 30 secs of thinking time.

Just gotta work out what the hell XP is doing!

That's weird! It's normally the other way round - Vista runs like a dog and XP is fine
Good old Microsoft!
Matt

Many thanks for your comments on my issue.

Woodworm, I already have an external drive and a weekly backup schedule, but Sod’s law dictates that disaster will strike at the worst possible time. I also run 64-bit Win XP on my main machine and strongly suspect I would face a mountain of trouble using data restored to another operating system; would much prefer to minimise the risk of having to go that route in every way possible.

Iceblinker, I also have Dell, and the machine in question has a 5000x motherboard, while the system reports that the Raid controller is called Intel 631ESB/632xESB which I assume is onboard.

My Dell documentation makes no reference to the possibility of running multiple Raid configurations, but the Intel configuration utility (Matrix Storage Manager) help file in fact does:

“RAID 10 (Striping and mirroring)

RAID level 10 uses four hard drives to create a combination of RAID levels 0 and 1. The data is striped across a two-disk array forming a RAID 0 component. Each of the drives in the RAID 0 array is mirrored by a drive in the RAID 1 array. This configuration provides the benefits of the performance of RAID 0 and the redundancy of RAID 1.”

This sounds like exactly what I am after but there are two problems. Firstly the documentation appears to say it is impossible to migrate from a 2 disk Raid 0 to a 4 disk Raid 10. I find that odd given the description and wonder whether they merely mean that you can’t convert a 2 disk array to a 4 disk due to the laws of physics. Do you have any info on this?

My second problem is that the computer chassis only has dedicated space for a 3rd hard disk according to the documentation. I need to open the thing up and see if I can cram an extra one in there somewhere; perhaps I’ll be able to swap one for the 3.5” floppy drive I originally believed to be a configuration masterstroke but have subsequently not used once However, any tinkering is going to have to wait until things calm down considerably in my day job.

I have a different Intel controller (82801 GR/GH) - but I wouldn't be surprised if yours offers the same or similar facilities.

It's not obvious from DELL's documentation that I can have more than one array, but in fact it's done simply by first creating an array that is smaller than the maximum capacity. The second array then uses the remaining space. (No more than two arrays are allowed). I think three disks could be used with two arrays, with any combination of RAID 0 and RAID 1. (RAID 1 would go on any two of the discs, RAID 0 on any two or three).

I haven't looked much into RAID 10 yet (because I don't fancy having four disks running all the time). I would have thought it's physically possible to do the migration you want automatially, but perhaps Intel haven't bothered to provide the facility. In this case, you would have to copy your existing disk contents to a backup disk, create a new 10 array (which will blank everything on your four main discs), and restore your backup to the new array. This would be easy with Acronis True Image or Disk Director.

If you have a spare SATA socket inside the computer, you could easily have another disk outside the computer permanently and running just as if it were an internal drive.

I've recently done this myself by installing SATA ports ( http://tinyurl.com/4tt7dv ) and putting the disc in a Scythe QuietDrive case. This thing is meant to be fitted inside a PC, but actually makes a nice external enclosure as well.

Power can come from inside the computer, or outside from a separate power supply. I happen to have a SATA bracket on eBay without a power socket at the moment: http://tinyurl.com/4abu2o

Currently I have Windows on one disk (non-array), and my data on two other disks with one big RAID 0 array for the bulk of it, and one small RAID 1 array for some most important stuff. I regularly backup everything to a USB/Firewire external drive.

I also have a floppy drive installed that I don't use. The bay could be used for another internal hard disk. But I think I'll leave it in just in case I come accross an interesting floppy disk one day!

Thanks very much for your detailed notes Pete.

My inclination would be to keep everything out of sight within the box and I do have a spare bay under my DVD drive that I see no reason why I shouldn’t be able to use, except that the documentation seems adamant that it is for an optical drive only.

That said I must say your external solution looks quite nifty; I had no idea such something so elegant was possible.

Again many thanks.

Problem solved accidently! Needed to disable anti virus to run a program, then went to do some work involving the NAS, and bingo, it was flying!

Odd behavior to be caused by an anti-virus program. I could see constant slow access, but slow start up seems weird.

Which was it Norton or McAfee? (hate both with a passion for their total disregard for system resources and stability) If another, I'd be interested in putting it on my "stay away" list.

Anyway congrats on finding the cause. Now, how to fix??

It is a weird one as I knew from using it with Vista that there was nothing wrong with the NAS, but taking over 10 minutes to show the icons of files in a directory really was taking the ****!! Hopefully it is the solution to my age old problem of windows taking upto 5 mins to redraw desktop icons (and bringing the system to a halt) as well!

The antivirus in question is AVG, will uninstall from at least one machine tomorrow to see how I get on.

Sorry to resurrect this thread but I now have a bit of spare time and still need to sort out my backup situation previously discussed here in some detail.

My original Raid 10 idea has pretty much been mentally binned, since as Pete said it is just too many disks to have spinning at once, but I still want to implement something with near bullet proof redundancy.

I have instead given more thought to Pete’s idea of a having an external drive running off an existing internal SATA socket. I quite like this and certainly have at least one spare socket but am concerned that you couldn’t switch off the external unit in isolation without developing system instability (eg a drive suddenly disappears and the OS hangs). Pete, do you have any insight into whether that is possible?

In any case I am increasingly drawn towards something along the following lines: http://www.amazon.co.uk/EdgeStore-DAS501T-Bay-eSATA-Enclosure/dp/B001H54JX6/ref=sr_1_2?ie=UTF8&s=electronics&qid=1234818683&sr=1-2

This offers far more storage potential than I will need for the foreseeable future. However, my idea would be to populate it with say 2x 1Tb disks (any model suggestions?) that I would effectively mirror at least weekly with a scheduled incremental data backup, and then physically evacuate (perhaps in a caddy) when travelling for off site backup. Does this sound insane or sensible?

FWIW, my basic requirement is to do nightly/as required back ups of a MySQL database of around 7Gb (spread over only a few files that are all updated daily) and ideally also my Outlook .pst file presently weighing in at just under 3Gb in 5 minutes or less.

Any comments or alternative suggestions gratefully appreciated.