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I just posted about finding bottle necks and have narrowed it down to having way too many VMs on my machine on one 15K SAS drive. I have plenty of cores and plenty of ram.

So I am planning on putting 6 VMs on one drive (so 5 drives for 30 VMs). I am thinking of using a 60GB Vertex 2 SSD. Each of my VMs will only need about 6GB of HDD space so this isn't a big deal.

My questions are:

  • does ESXI support Trim and do I really need it if I leave 25% of the drive as free space? If I need it should I get a diff drive that handles garbage collection differently?
  • Is there anything I need to consider regarding SSD's in virtualized environments.

Thanks for any and all help!

UPDATE: So the main question if I use a 60GB drive and leave 20GB free how badly will the drive degrade due to a lack of Trim? What about if I get a drive such as the Kingston SSDNow V+100 with hardware os-independent garbage collection??

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2 Answers

up vote 1 down vote accepted

ESXi does not support trim directly as noted in the following post:

Trim on intel x25-m G2 when connected by iscsi

There are examples of people using SSD drives on ESX(i) systems, though. My question for you is if you have the ability to actually run with more traditional SAS drives? You could probably support your VM load on 6 drives in a RAID 1+0 setup with 15k drives and a write-caching controller. Are there some other limitations that you're not sharing here?

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Its purely financial, the SSD drives work out cheaper and you get WAY more performance out of them. Space isn't what I need, its performance. –  nextgenneo Feb 5 '11 at 22:47
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I don't think ESX supports TRIM but its quite hard to find documentation either way.

Based on my experience of ESX, I'd be more comfortable with spreading the VMs out over several fast but conventional disks. If you have a good RAID controller that's supported by ESX then to be honest I'd probably just use that and split the load between a couple of disk arrays.

At the end of the day, what's more important - to be a pioneer or to have a reliable system?

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