Question About Disk Performance

[abitguru]

Hi all, i cant think about an apropieted subject for the topic.

Here is the thing.

We have a Server with this specs

Windows Server 2008
8 x Intel Xeon L7555
32 GB Ram
RAID 5 with SAS disks. poweredge storage-

In the server we have

SQL Server 2008
17 GB
5 Cores

15 GB for windows only.

Our company system hosted (app based on Visual fox pro 9)

When we test the storage via Performance Monitor and HDTach, we have 22 MB MB/s for average read (disk) (hdtack)

I think this is ridiculous becouse the hardware we have (i must say i'm not a

I ask here because we are encharged of sql server, no the hardware of the server, and i'm not a specialist hardware guy, but you dont have to be an especialist when see something like this.

I investigated performance monitor, with some Windows Server counters and I reach to the conclusion that we have a serious bottleneck problem.

Sorry for my out of practice english.. and what do you think about this (if the server is affected by disk performance)

The problems we have.. for example.

We copy a backup of SQL Server (80GB) from the main server to other server.. and literaly noone can use the system and the net colapse.
Yes, the other day we made the test, 1 minute to access the system (variable but a long time)
When the transfer finish, everything comes to normal.

Other important point, every transfer we made between servers is about 15-30Mb/s. I think this is too slow but.

I think this is one big problem that affects performance in many ways, but I need your opinions with experience



Thanks !!!

 

[ICTCity]

Hi, I have many ideas but first a question:

Yours disks are on the LOCAL SERVER or on a SHARED STORAGE (NAS - SAN)? If so (I think it is because of "poweredge storage"), do you have a dedicated network for your storage and a separate for "LAN" traffic?

 

[abitguru]

sorry i dont know much of config, i'm a programmer the it guy hire dell suport to configure all.

1 shared storage
2 i think its the same lan

thanks so much

 

[ICTCity]

You've found the solution

You're already lucky with 20 MB/s on the same network... really!

You should tell somebody (who installed the network) to SEPARATE the networks.

So basically:
2 VLANs:
1 for LAN
2 for STORAGE

On your windows box you will have AT LEAST 2 NICs one for LAN and the other for STORAGE.

Once done you will notice a speed up to 50 MB/s

Then of course you may have other problems like bad config of your storage or disks. But usually when somebody tells me that the storage is slow the answer is NETWORK!

If you need further help feel free to ask.

 

[abitguru]

thanks this is valuable info, now i'll ask for how the storage is config.

the storage must be in a diferent lan with the users/system lan? right? (for confirmation if I understand)


you really help me !!!

 

[ICTCity]

Yes you're right. This is called VLANs.

Don't spend too much time on the storage config, most of your problems are related to the network trust me.

 

[abitguru]

Thanks ICT, is there a simple way to check if there are on the same LAN??? (sorry i'm really noob on storage config)

 

[ICTCity]

well more or less yes...

Go to the server and type (command prompt) ipconfig and write down the IP. Then do the same thing on the storage (you should login into your dell and somewhere you should see the network configuration), write down all the IPs that you can find.

If you prefer you can post pictures.

If the IPs are on the same class, then you are on the same network. If you don't know how to notice this, simply post the IP addresses.

 

[abitguru]

Thanks again ICT..

I've new info..

here an ipconfig of the server

(trick because i cant post pics already)

LAN STORAGE
IP: 192.168.100.25
MASK: 255.255.255.0

LAN SERVER
IP: 10.95.8.50
MASK: 255.255.252.0

more info, the server has 4Gb of bandwich

and sorry for the bad config info I gave you.

I hope this helps to find another config problem.

thanks a lot for your help.

 

[ICTCity]

So the network is separated... just a question... which services are running on that storage? SQL, then? How many VMs? How many PHISICAL DISKS do you have in your storage?

 

[abitguru]

The services running on the server are:

Virtual Windows Server 2008 (not R2)

SQL Server 2008
2 company system one based on vfp 9 and other based on vfp 2.6 (some dbf tables not very large, most data is on SQL server)

We test with HDTach on Win 2008 Server and we get a 22.8 MB/S AVG Read
We test with HDTach on a Clean Windows Server R2 311 MB/s AVG Read.

i dont have the info about physical disk.

thanks a lot.

 

[ICTCity]

SQL is RAM and DIsk consuming, but a drop from 311 to 22.8 looks a bit too much. Said that... do you have SSDs or HDD? Because 311 it's really a high value!

What I think right now is that you have many concurrent operations to your shared storage. If you open the RESOURCE MONITOR and expand the DISK section (do not log, just watch) during queries and so on, do you notice a high value of the process sqlserver.exe OR networkservice.exe or other? When I say high value I mean something greater than 30 MB/s.

Another thing. How do you have installed your sql? Windows and sql on the same partition?

 

[abitguru]

Thanks!!!

1 - HDD, not SSD
2 - I will watch the way you say in resource monitor
3 - SQL Server is install on windows partition, but data is in another separed disk, and log too.

 

[ICTCity]

Ok, I wait until you tell me the perfomances seen on res monitor.

 

[abitguru]

I've a screen but i dont know how to post it here besause i dont have 20 post already.

 

[ICTCity]

Yeah I know... PM links to me (upload somewhere).

 

[abitguru]

sorry for the trick, but i cant find how to send PMs, don't know if its permision or what, but if you enter in my profile I put the image on Skype info.

Sorry for doing this way but I cant find other (i think is because i'm newbie)

thanks. (let me know if you see the pic)

 

[ICTCity]

The picture was taken when the server is at full load?! it's doing nothing...

I saw that you have nod32... try to disable the NETWORK DISK SCANNING (I can't remember the exact sentence) and make sure that the SQL executable is disabled.

Just to try, disable nod32 and try if the situation goes better.

 

[abitguru]

Thanks ICT, i can't disable SQL because its a production server.

I cant disable nod32 because it managed by other department, i'll ask for that.

Now I put a pic with a very larga SQL statement, hope this helps!!

Thanks

 

[ICTCity]

Do not disable SQL, exclude it from nod32 real time scan.

It looks like another situation that happened to me. The problem was the same... I hope that if you disable nod32 the situation will be better. If not we must follow the others options.