FreeBSD VM: Slow Disks

[AthenaL]

Hello everybody

I'm a relatively experienced sysadmin but new to virtualization so please excuse any lack of knowledge.

I have been playing around with ESXi in the hope of consolidating some of my FreeBSD machines. All seems to work really well with the exception of what seems like really slow virtual disk access. I have tried both the buslogic and LSILogic disk controllers but both seem inflicted with the same performance problems.

My tests were performed on the same hardware using the following crude benchmark: $ time { tar xzvf ./linux-2.6.25.tar.gz; }; averaged over 5 runs and the results were as follows:

1] Machine running FreeBSD as a native OS: Real: 0m17.820s; User: 0m2.100s; sys: 0m2.001s

2] Machine running FreeBSD as a guest of ESXi: Real: 2m35.937s; User: 0m14.882s; sys: 1m3.912s

Also buildworld took about 3 hours longer than the native install did.

I ran these tests both using the buslogic and LSILogic controllers and found the LSILogic to be slightly faster. I'm not sure if this really is a performance issue or if its about what I can expect for a VM.

Can anybody offer any assistance?

Thanks in Advance

Athena

[mcowger]

Do you have tools installed?

--Matt

[wpatton]

Ensure VM Tools are installed. The LSI is a better controller, I would stick with that for FreeBSD.

Also, is the storage backend between your physical test system, and your virtual test system different?

If you found this or other information useful, please consider awarding points for "Correct" or "Helpful".

[AthenaL]

Hi & thanks for your response

Yes, I have the freebsd-tools installed but they don't seem to provide a better disk driver. Is there a module I should be loading? FreeBSD tools are from VMWare-server-1.0.4!

My tests were conducted on exactly the same hardware, including disks. The hardware is quite basic really consisting of a Pentium 4 650 with 2GB RAM and a internal SATA150 drive. I have a Adaptec 320Mbit RAID card with three 15k disks which I'll try later tonight configured in RAID0.

Thanks

Athena

[wpatton]

Just to be certain we are all speaking the same language. By "freebsd-tools" do you mean the "VMWare-Tools"? They are the perl packages that need to be installed on each client machine. They contain all the supported and tested driver files, etc.

Also, what version of FreeBSD are you running?

If you found this or other information useful, please consider awarding points for "Correct" or "Helpful".

[AthenaL]

Hi wpatton

Again thank for your help.

Yes sorry I did mean VMWare tools (for FreeBSS) Im running 7.0-STABLE and suspect that this is what the problem is. I have just noticed that the vmware-tools did not install correctly and was bombing out. I have just downloaded vmware-server-2 and am about to test using the newer version of vmware tools.

It looks better already...

Athena

[wpatton]

Yeah, that is what I was afraid of, 7.0 isn't supported yet. I doubt it is far away, but for now you might experience some issues. Glad to hear Server 2.0 is helping you out though!

If you found this or other information useful, please consider awarding points for "Correct" or "Helpful".

[AthenaL]

Hello again

I seem to have vmware-tools installed and running - at least 'ps axu | grep vmware' shows a process running but its not helped the disk performance. In fact, I still cannot find a module for the disk controller so currently I'm running with the standard mpt0.

What concernes me is that 'dmesg' shows:

'da0: 3.300MB/s transfers' --- Thats DOG SLOOOOOW.

Any more ideas on how to improve my disk throughput?

Thanks

Athena

[wpatton]

I hate to say it, but until 7.0 is supported as a guest os, you might have to wait or go back to 6.2.

If you found this or other information useful, please consider awarding points for "Correct" or "Helpful".

[AthenaL]

I was afraid you say that :_|

I dont really want to go back to 6.2 so think i might live with the performance issues - after all the VMs will only be lightly used.

Any idea how long before 7.0 is supported?

Once again, thanks....

[wpatton]

Yeah, I hate resorting to that, but it looks like that might be the issue here.

For expected support timeline, I couldn't guess, but I wouldn't worry terribly since VMWare adds support for continued versions of existing supported OS lines really quickly.

If you found this or other information useful, please consider awarding points for "Correct" or "Helpful".

[s_shino]

Hello Athena

> 'da0: 3.300MB/s transfers' --- Thats DOG SLOOOOOW.

Is the throughput improved by the following command?

camcontrol negotiate 0:0 -a -O 127 -R 160 -W 16

This command needs supporting passthrough device(device pass) in your kernel.

[AthenaL]

Hiya

Thats good - it gives about a 15% improvement :smileycool: Still slow though...

What's the best way to make this command survive a reboot?

Thanks

Athena

[AthenaL]

Problem SORTED :D:) :):D

Firstly I installed OpenBSD-4.3 and run the same benchmark and found that OpenBSD was at least 100% faster. I then created a new VM and installed FreeBSD-7.0-RELEASE and retested and this time i had a 150% improvement :smileygrin: Thats without the vmware-tools installed WOW!

At this stage I think the problem is either with FreeBSD-7.0-STABLE or quite simply it was just a bad install - more testing required...

Great work - thanks a million guys; you were great!

Athena