# Database performance slow on Windows DomU **URL:** \ **Category:** SLES Virtualization\ **Created:** [February 9, 2014, 12:29am UTC](https://forums.suse.com/t/database-performance-slow-on-windows-domu/25103 "2014-02-09T00:29:52Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![stelgenkamp](https://avatars.discourse-cdn.com/v4/letter/s/76d3ee/32.png) [@stelgenkamp](https://forums.suse.com/u/stelgenkamp)\ **Post date:** [February 9, 2014, 12:29am UTC](https://forums.suse.com/t/database-performance-slow-on-windows-domu/25103/1 "2014-02-09T00:29:52Z")
Hello Everyone, I could use your advise on the following : I am running Xen on SLES 11 SP3 On this I have a Windows 7 Pro VM, running a Sybase database. Database performance is, well, not fast. I have the 2.1 VMDP installed. Also I did all the LSO offloads on both the DomU and the DOM0 I also have a OES11 DomU working with my Raid where I have my volumes Since the database is the companies main program, performance is important Now I have been checking the throughput with Iperf. Windows DomU =\> Dom0 87 Mbit/s Dom0 =\> OES11 DomU 5.35 Gbit/s Windows DomU =\> OES11 DomU 84.6 Mbit/s On standard file copy from Windows DomU to OES11 DomU, I am getting 10.000 KB/s which is about the 80 Mbit/s But when doing a backup from the Sybase database I am only getting 3000 KB/s only. Can anyone confirm these throughput speeds are normal ? Anyone ideas what could be causing the delay in database speed ? Thanks, Stephan ---
**Author:** ![ab1](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@ab1](https://forums.suse.com/u/ab1)\ **Post date:** [February 9, 2014, 6:12am UTC](https://forums.suse.com/t/database-performance-slow-on-windows-domu/25103/2 "2014-02-09T06:12:58Z")
Is there some reason you are ruling out this as a Sybase issue? If the problem only happens when using application X, and particularly when application X may need to be doing a lot of other stuff at the time to aggregate the data for the backup process, does that not seem to point at application X? If you have this same setup but with Sybase in another virtual environment (KVM, for example) or if you have another database involved (MariaDB/MySQL, or PostgreSQL, for example), do those behave differently or similarly? What kind of Sybase backup (including commands) are you doing? Is Sybase needing to read all of the data at the same time it is writing out, and is it doing so from the same disk or disk system for both operations? – Good luck. If you find this post helpful and are logged into the web interface, show your appreciation and click on the star below… ---
**Author:** ![stelgenkamp](https://avatars.discourse-cdn.com/v4/letter/s/76d3ee/32.png) [@stelgenkamp](https://forums.suse.com/u/stelgenkamp)\ **Post date:** [February 9, 2014, 12:10pm UTC](https://forums.suse.com/t/database-performance-slow-on-windows-domu/25103/3 "2014-02-09T12:10:25Z")
Dear Ab, Yes this maybe related to the application. However this is the companies main program, and this uses the sybase database. So changing the database is out of the question. The VM only runs this program and database, it does nothing else. I have assigned 4 cores to the VM, but it does not seem to matter in speed. Also assigned 4 Gb of memory, to try and speed up everything. The VM is running on a 80 Gb raw image file. So what is your opinion on this setup ? any recommandations ? Can you confirm these throughput speeds are normal for a Windows VM ? Any other ideas what could be causing the delay in database speed ? Stephan ---
**Author:** ![KEVIN1](https://avatars.discourse-cdn.com/v4/letter/k/a9adbd/32.png) [@KEVIN1](https://forums.suse.com/u/KEVIN1)\ **Post date:** [February 10, 2014, 10:01am UTC](https://forums.suse.com/t/database-performance-slow-on-windows-domu/25103/4 "2014-02-10T10:01:48Z")
stelgenkamp wrote: [color=blue] > Anyone ideas what could be causing the delay in database speed ?[/color] Over the past several releases a variety of issues have surfaced relating to TCP offloading in general and TSO offloading in particular. If you search the knowledgebase for “ethtool” you can see some of them. [http://www.novell.com/support/](http://www.novell.com/support/) Try to disable all offloading in DomO and DomUs and see if throughput improves. Try to enable them one at a time to see how throughput is affected. – Kevin Boyle - Knowledge Partner If you find this post helpful and are logged into the web interface, show your appreciation and click on the star below… ---
**Author:** ![stelgenkamp](https://avatars.discourse-cdn.com/v4/letter/s/76d3ee/32.png) [@stelgenkamp](https://forums.suse.com/u/stelgenkamp)\ **Post date:** [February 10, 2014, 11:39am UTC](https://forums.suse.com/t/database-performance-slow-on-windows-domu/25103/5 "2014-02-10T11:39:53Z")
Hai Kevin, I did all the TSO and LSO offloads on both the DomU and the DOM0. Any other recommandations ? Can you confirm these throughput speeds are normal for a Windows VM ? Any other ideas what could be causing the delay in database speed ? Stephan ---
**Author:** ![ab1](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@ab1](https://forums.suse.com/u/ab1)\ **Post date:** [February 10, 2014, 2:01pm UTC](https://forums.suse.com/t/database-performance-slow-on-windows-domu/25103/6 "2014-02-10T14:01:24Z")
On 02/09/2014 03:14 AM, stelgenkamp wrote:[color=blue] > Dear Ab, > Yes this maybe related to the application. > However this is the companies main program, and this uses the sybase > database. > So changing the database is out of the question.[/color] I’m not suggesting changing the database system, just verifying that this is part of that program and not the overall environment. Until we know more about what is happening knowing if it is normal or not is tricky. [color=blue] > The VM only runs this program and database, it does nothing else. > I have assigned 4 cores to the VM, but it does not seem to matter in > speed. > Also assigned 4 Gb of memory, to try and speed up everything. > The VM is running on a 80 Gb raw image file.[/color] Do you think this is a problem with processing power for some reason? Are you seeing contention on the virtual processors during these operations? My original response, about testing other databases and asking what else the database was doing at the time, was not meant to be limited to processing. Your initial complaint is about I/O, and usually I/O becomes slowed significantly by other I/O (for example, if your database is running normally and doing normal reads and writes at the same time you are trying to have it create a backup) so I would probably focus more on the disk system than processor and RAM unless you have evidence proving the problem is due to a limitation of processor and/or RAM. [color=blue] > So what is your opinion on this setup ? any recommandations ?[/color] Same as before. Test other systems to verify this is (or is not) related to the application. Post the actual commands being used that show the slowness. Other ideas: try swapping out the OS. windows isn’t known for high-performance (see the top 500 supercomputer list, for example) and chances are that a DomU running Linux can perform better, assuming this is at all related to the OS itself (I recall that Sybase is cross-platform… correct me if wrong). I wouldn’t try this first though, since the evidence still seems to point at limitations on the application side. [color=blue] > Any other ideas what could be causing the delay in database speed ?[/color] Just what is mentioned above. Find the bottleneck based on evidence and then test things that will help you verify or rule out hypotheses. This is the reason for the suggestion about trying another DB for testing, or stopping all other database activity when doing the backup, as well as requesting the commands used. For example, if the commands used are simply copying database file within the operating system (meaning the database itself is not involved) then the database itself should not matter and now you have an OS issue. On the other hand, if the commands are within Sybase and instruct the system to, while doing production work as well, create a backup of the database then you are now adding work o an application that may already be I/O constrained, or to a system that may already be I/O constrained due to the application doing reads/writes to the same database (and system) that is now going to be used for creating the backup. – Good luck. If you find this post helpful and are logged into the web interface, show your appreciation and click on the star below… ---
**Author:** ![KEVIN1](https://avatars.discourse-cdn.com/v4/letter/k/a9adbd/32.png) [@KEVIN1](https://forums.suse.com/u/KEVIN1)\ **Post date:** [February 10, 2014, 6:11pm UTC](https://forums.suse.com/t/database-performance-slow-on-windows-domu/25103/7 "2014-02-10T18:11:49Z")
stelgenkamp wrote: [color=blue] > I did all the TSO and LSO offloads on both the DomU and the DOM0.[/color] I’m not sure what that means… I’m suggesting you disable all offloads to see if it helps your performance. If ethtool shows it enabled, disable it. [color=blue] > Can you confirm these throughput speeds are normal for a Windows VM ?[/color] No I can’t but they seem low. – Kevin Boyle - Knowledge Partner If you find this post helpful and are logged into the web interface, show your appreciation and click on the star below…