Quick question about Dell r720 options of disk and CPU?

[killmasta93]

Hi,
I was wondering if someone could shed some light on a few questions i have.
Currently bought a dell r720 with 192 gigs of ram with 2x 2.90Ghz E5-2690 8 Core Processors, and 10 disks SSD 800 gigs with IT mode dell H310mini.
I was reading about the configuring the VM there's a few options im confused.

1) As for ZFS i would guess putting it on a RAID 10? as i need the best configuration for speed as the VM thats going to be running is MSSQL on windows server 2012r2

2) for that VM which is going to have MSSQL would i use the VirtIO Block controller and check mark the SSD emulation? Because as reading on the wiki it says

Note that Discard is not supported on VirtIO Block drives.

3) it also says that the IO Thread enable would work faster but its not able to backup on vzdumps?

Note that backups do not currently work with IO Thread enabled.

4) as for the disk cache it says the best would be the no cache?

The No cache default means that the guest system will be notified that a write is complete when each block reaches the physical storage write queue, ignoring the host page cache. This provides a good balance between safety and speed

but even though i have a VM with MSSQL?

5) As for CPU socket currently have SQL standard, correct me if im wrong the standard 2012 allows me with 4 cores?
So in this case whats the rule of thumb for the sockets and core? as for the NUMA would be recommended to enable it?

the memory is spread into local banks close to each socket. This can bring speed improvements as the memory bus

but are they talking about memory of the CPU or the memory of the ram?

Thank you

 

[wolfgang]

Hi,

1.) As your r720 use an H310mini it is not recommended to use ZFS.
ZFS is not compatible in general with Raid-Controller.

2.) If discard is not supported windows will send discard commands(trim) but it will be ignored.

3.) VZ Dump work with IO Thread. Can you provide the source of this statement?

4.) This dependence on the underlying storage system. In ZFS case it is true. Because ZFS has an own cache and with a second cache you do mem copy.

5.) This is a Microsoft License problem and I can't say anything to this.
In the case of performance.
With the assumption, you do not use more cores and memory than a single socket can provide.
Use NUMA and restrict it to one socket [1].

1.) https://pve.proxmox.com/wiki/Manual:_qm.conf

 

[killmasta93]

Thanks for the reply,

As your r720 use an H310mini it is not recommended to use ZFS.
ZFS is not compatible in general with Raid-Controller.

the h310mini is flashed IT mode to work as an HBA mode forgot to mention, but what RAID setup would be the recommendation? Raid 10? with the 10 disks SSD?

2.) If discard is not supported windows will send discard commands(trim) but it will be ignored.

So instead of discard would i enable SSD emulation?

3.) VZ Dump work with IO Thread. Can you provide the source of this statement?

4.) This dependence on the underlying storage system. In ZFS case it is true. Because ZFS has an own cache and with a second cache you do mem copy.

so keep as in no cache? for the disk?

5.) This is a Microsoft License problem and I can't say anything to this.
In the case of performance.
With the assumption, you do not use more cores and memory than a single socket can provide.
Use NUMA and restrict it to one socket [1].

so one socket and always habilitate NUMA? so whats the case when not to activate NUMA?

Thank you

 

[wolfgang]

Raid 10? with the 10 disks SSD?

Yes, raid 10.

So instead of discard would i enable SSD emulation?

This would not work. Windows would trim but it has no effect.

I guess you have an old Doku because in the current docu there is no such information.

so keep as in no cache? for the disk?

If you use ZFS yes "no cache" for the vdisk.

so one socket and always habilitate NUMA? so whats the case when not to activate NUMA?

The kernel will distribute the memory on the node and you have NUMA memory misses.

 

[killmasta93]

Thanks for the reply, so just configure the disks as default with the Virtio drivers so the SSD emulation when would I apply it??

Thank you

 

[wolfgang]

At the VM setup time.
Use always discard and SSD emulation this does not hurt.

 

[killmasta93]

thanks for the reply, so always check discard, and SSD emulation only if the host has SSD on the pool? what about the IO thread?

Thank you

 

[wolfgang]

You have to choose what you need. Not all combinations are possible.