Comments on: Awesome performance through VMware DRS http://www.vcritical.com/2009/07/awesome-performance-through-vmware-drs/ Informed Virtualization Criticism Fri, 10 Sep 2010 16:25:13 -0700 http://wordpress.org/?v=2.9.1 hourly 1 By: Eric Gray http://www.vcritical.com/2009/07/awesome-performance-through-vmware-drs/#comment-6961 Eric Gray Fri, 17 Jul 2009 17:26:00 +0000 http://www.vcritical.com/?p=1237#comment-6961 Jonathan, thanks for your input here. As you say, DRS works great with clusters larger than 3-4 nodes. I suspect folks doing tests and experiments just want to create a sample environment that is fully functional while minimizing the logistical burden, thus 3-4 nodes. BTW, I was debating how to handle Alex's comment -- it's obviously plugging his startup. I decided to let it stand. Jonathan, thanks for your input here. As you say, DRS works great with clusters larger than 3-4 nodes. I suspect folks doing tests and experiments just want to create a sample environment that is fully functional while minimizing the logistical burden, thus 3-4 nodes.

BTW, I was debating how to handle Alex’s comment — it’s obviously plugging his startup. I decided to let it stand.

]]> By: Jonathan http://www.vcritical.com/2009/07/awesome-performance-through-vmware-drs/#comment-6958 Jonathan Thu, 16 Jul 2009 22:27:03 +0000 http://www.vcritical.com/?p=1237#comment-6958 Alex, I have used DRS in larger clusters than that. In one environment for example, VC handled DRS for 4, 6, 12, and 16-node clusters in the same virtual datacenter. I never knew DRS to have any problems. Alex,

I have used DRS in larger clusters than that. In one environment for example, VC handled DRS for 4, 6, 12, and 16-node clusters in the same virtual datacenter. I never knew DRS to have any problems.

]]> By: Alex Miroshnichenko http://www.vcritical.com/2009/07/awesome-performance-through-vmware-drs/#comment-6924 Alex Miroshnichenko Sat, 11 Jul 2009 00:17:32 +0000 http://www.vcritical.com/?p=1237#comment-6924 Eric, Great post, thank you. It is great to see DRS – the first practical automatic load balancer. Do you know what are the real scalability limits of DRS today - I have yet to see any mentions of beyond 6-8 physical servers... Also to the best of my understanding DRS does not take into account the disk i/o channel loads – is this true ? It would explain the huge cost of the storage used in the test. My back-of-the-envelope calculations for the test above show that the storage is about 20-25 times (yes, times) more expensive than the servers (more details at blogs.virsto.com). Wouldn't it make more sense to save on storage ? Thank you, Alex. Eric,

Great post, thank you. It is great to see DRS – the first practical automatic load balancer.

Do you know what are the real scalability limits of DRS today – I have yet to see any mentions of beyond 6-8 physical servers…

Also to the best of my understanding DRS does not take into account the disk i/o channel loads – is this true ? It would explain the huge cost of the storage used in the test.

My back-of-the-envelope calculations for the test above show that the storage is about 20-25 times (yes, times) more expensive than the servers (more details at blogs.virsto.com).

Wouldn’t it make more sense to save on storage ?

Thank you,

Alex.

]]> By: Eric Gray http://www.vcritical.com/2009/07/awesome-performance-through-vmware-drs/#comment-6919 Eric Gray Thu, 09 Jul 2009 23:17:26 +0000 http://www.vcritical.com/?p=1237#comment-6919 Brandon, That's a great question, and I hope your testing goes well. Virtual machines cannot use resources from multiple hosts simultaneously, so your SQL Server would need to migrate to another host with more RAM. However, DRS could still help you in this case by shuffling the VMs around in such a way that frees up the most amount of RAM for your DB. Eric Brandon,

That’s a great question, and I hope your testing goes well.

Virtual machines cannot use resources from multiple hosts simultaneously, so your SQL Server would need to migrate to another host with more RAM.

However, DRS could still help you in this case by shuffling the VMs around in such a way that frees up the most amount of RAM for your DB.

Eric

]]> By: B. Riley http://www.vcritical.com/2009/07/awesome-performance-through-vmware-drs/#comment-6917 B. Riley Thu, 09 Jul 2009 19:15:58 +0000 http://www.vcritical.com/?p=1237#comment-6917 Eric: I am about to build a DRS cluster for testing. One thing I am a bit confused about is whether VM's can use resources from more than one host at a time. Example: If I have a SQL box that gets max'd out and needs more RAM, can it use RAM from another host in the cluster? Or does is it constrained to finding a single, larger host? Thanks! Brandon Eric:

I am about to build a DRS cluster for testing. One thing I am a bit confused about is whether VM’s can use resources from more than one host at a time.

Example: If I have a SQL box that gets max’d out and needs more RAM, can it use RAM from another host in the cluster? Or does is it constrained to finding a single, larger host?

Thanks!

Brandon

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