We help IT Professionals succeed at work.

New NAS is causing very slow directory listing on mapped drives

Jasonm71 asked
Medium Priority
Last Modified: 2008-03-14
I have a SBS 2003 Std Ed server, contains 2 nics 1 internal and 1 external.  The NAS has been added to the internal network.  Thecus 5200 with Raid 10 Config with WD 500GB HD.

We have 6 mapped drives on each workstation login, so I installed the NAS copied all the files over about 350GB in over night.  I had load balancing activated on the NAS NICs I now have only one NIC activated to assist in getting the problem solved.  I have a netgear 8 port Gigabit Switch about a year old and downstream a 24 port 10/100 Dell (2324 I think) All users are on the Dell switch.  Only Server/NAS/Backup workstation are on the gigabit.

The problem - when opening a mapped drive on the server it is nearly instant when we open a mapped drive on the NAS it takes a long time (say 10 minutes). It is driving my users nuts and had to be taken off line.

Deleted by Computer101, 500 points refunded. - 2/9/2008 2:17:02 PM
Watch Question

what is the speed of the internal nic and external nic
why are you connectring it to a server rather to the LAN
why raid 10 do you need a stripe set with mirroring this is a greater overhead that raid 5 or 6


Sorry Everything is question is internal, I thought I should mention the external nic in ther server just in case I missed something.  

The NAS is connected to the Gigabit Switch as is the server, the workstations are on the 100 switch which is off the gigabit switch.

I have chosen Raid 10 with 512 KB Stripe.  I chose the raid 10 as it is mirrored, maybe could have gone with raid 5.
you could try http://www.iozone.org/  to get software benchmark the speeds
whaat are the write speeds like compared to read

how is file and share security handled on the NAS ?

is it AD integrated ?

network speed above 100M should be barely noticable.

you map a drive  Net use X: \\NAS\SHARE1  ok ?

then trying to open X: in winexplorer takes the time ?

(must be getting desparate 8:30pm on a public holiday)


The Thecus is AD Integrated.  Mapping using net use yep, then try opening x: yes

a little desparate

which command takes the long time from a user PC?
Mapping or opening.

does a dir X: take time as well ?


Thanks for getting back.

The slow bit. Click on X: drive in say windows explorer.  Directory listing takes a long time (say count to 10).  Remembering X: is mapped to the NAS.  If X: was mapped to the old server it is nearly instant to open.

The NAS is also producing poor performance with software (Currently tested MYOB and AutoCAD) - Appearing to lock up performance.

I am still trying to run a benchmark on the network.
try DIR X: from command line. Just to take some of win overhead out of play.

does directory list from the server still work as expected ?
points away from hardware issue.

A couple of review sites i looked at indicated there had been issues with firmware needing to be updated,


still lags but not as great.

Have downloaded the latest firmware for the Thecus.

I am going to try taking off the AD see if that does it.


I turned off AD on some of the folders and it seems to be normal on those unsecure shares, must be something with AD lookups.

I would suggest that the question not be deleted as others looking will see that AD lookups are a likely problem and can then look to overcome issue.

Was there an AD fix available or did you just decide to live with lower security or did you return the device as not fit for purpose ?


Agreed probably best not to delete this question.Thank you for your help.

 I have decided to go with lower security for a while until I know the NAS  is stable.

I have not heard from Thecus support (yet!!!) and once I do I'll get into the AD issue.

It still is a good device at a reasonable cost.


Post the answer, I would like some assist points (250) to robberbaron.

Answer is, When connecting a NAS to an Active Directory only limit the authorised groups to a minimum say "domain admins" and "domain users".  The problem is that I authorised all available groups and users in the Active Directorylook up on the NAS.

So everytime we accessed the NAS it appeared to have looked (and maybe) updated the entire list.

By keeping it to the two groups the NAS with AD lookup performs as fast as the storage on SBS server.