ESXi - do I need a hardware RAID card

dave99 said:
I think that would be plenty. Mine is on 24/7, and the smaller 80mm fan is probably 4-5 inches away from the heatsink and it's fine. And if I remember correctly, I think I wired that fan down to 7v to make it quieter, so it's pretty slow also.
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Thanks for the post! That gives me confidence that mine should be alright from a heat point og view.

As soon as I have it up and running I'll post an update.

Something weird I noticed is that the mouse cursor doesn't work when I am in the WebBIOS using IPMI.
 
So my mini-SAS to SATA cables arrived today so I was finally able to connect my two Samsung 840 Pro SSD drives to the RAID card. Unfortunately the battery has failed so I am waiting for a replacement. Does this affect read/write performance?

The M5015 does support 6gb/sec for SATA drives. One thing I noticed upon finishing my ESXi 5.5 install is that the SSD drives showed up as "non-SSD" drives in the datastores. I had to follow these steps to get them to show as SSD drives:


Enabling the SSD option on SSD based disks/LUNs that are not detected as SSD by default (2013188)

So far without the battery installed the speeds with the RAID card and SSD drives have been ummm slow. Each SSD drive is its own datastore and when copying a ;arge 4GB file between datastores I get about 75-100MB/sec and when copying a file between two VMs using the vmxnet3 NIC (speed of NIC shows as 10gbps) I get 60-100MB/sec which is appauling!

How or what do I need to do to improve the SSD drive speeds? Has it got to do with running the RAID card with no battery? The SSD drives are capable of 400-500MB/sec!

I have two SSD drives connected to one port on the RAID card. Each SSD is its own datastore and I am not using RAID currently while I test. I have two Windows 8.1 VMs running on this host...each VM stores its vmdk files on one of the datastores.

I must be doing something wrong as I thought having a RAID card with cache memory would allow me to unlock the potential of the SSD drives...
 
So after a bad start I have some good news :) I have changed the "Policies" settings on the virtual drives on the IBM M5015 as follows:

Disk cache: Enable
Default write: Always Write Back

Now when I copy 4GB file from one VM to another I get 400+MB/sec! The speed is just incredible and I am extremely happy now. I am hoping to have a replacement BBU by next week so I can change the Default Write policy back to "Always Write with BBU". Luckily I have a UPS so no big deal running without a BBU at this stage.

Currently I have installed ESXi onto the one SSD and this same SSD is a datastore. Is this a good idea? I know some people boot ESXi from a USB flash drive but I want to avoid this. Is installing ESXi to a drive being used as a datastore for VMs a good or bad idea?
 
Anyone? :D

I'm also curious to hear if anyone with the IBM MegaRAID M5015 card has used this exact card with Samsung Pro 850 SSD drives? Will these drives work correctly with this RAID card? Only reason I am asking is that these drives are not on their compatability list.
 
I just prefer to use a usb drive, I don't want my install and my datastores mixing.

Also, given the 850 is the same controller as the 840 pro just tweaked a bit, I'd wager a guess that you would be fine in a raid, but it's your data! ;)
 
dave99 said:
I just prefer to use a usb drive, I don't want my install and my datastores mixing.

Also, given the 850 is the same controller as the 840 pro just tweaked a bit, I'd wager a guess that you would be fine in a raid, but it's your data! ;)
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I am going to stick with the 840 drives. I don't want to risk the 850s!

I have been reading about "over-provisioning" (OP) with SSD drives. I think what I am going to do is connect 4 SSD drives (two 128GB drives and two 512GB) to the RAID controller and not use RAID at all (even though its a single drive configuration it shows as RAID0).

Does anyone know how I should setup the OP with this type of setup. I have read that I should have at least 20% free space on the SSD drives as this will increase the life of the SSD and enable good performance.

So do I reduce the size of the SSD at the RAID controller level or when creating the datastore in ESXi?

What makes this even more confusing is that some people say you need 20% free space on your datastore. Is this in addition to the OP space? :confused:
 
I think if you are overprovisioning, the free space in the datastore isn't as important, but that's just a guess, one of the vmware experts here can give better guidance than I can.

I'd overprovision from the controller if you can, just so it's done at the base level.
 
dave99 said:
I think if you are overprovisioning, the free space in the datastore isn't as important, but that's just a guess, one of the vmware experts here can give better guidance than I can.

I'd overprovision from the controller if you can, just so it's done at the base level.
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Thats what I was thinking, do everything from the RAID controller point of view. So I was going to create a 409GB (80% of 512GB) partition on the 512GB SSD in the WebBIOS.
 
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