Dell PowerEdge repurposed

cyclones

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May 12, 2009
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We use Dell PowerEdge servers for all of our server setups. I am repurposing one to try out Proxmox to see if it meets our changing needs. However, I'm not sure how best to setup the server. I've looked through the forums and the how-tos, but haven't found what I'm looking for.

All of our servers are setup with one RAID 1 and a larger RAID 5 (120 gb and anywhere from 750 gb to 2 TB, both using hardware RAID). When I installed Proxmox VE it installed onto the RAID 1, but I'd like to mount the RAID 5 as a second LVM and use it as well for VMs. How do I do that?

Any suggestions for different configurations other than what I'm trying for?

Thanks!
 

dietmar

Proxmox Staff Member
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Apr 28, 2005
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All of our servers are setup with one RAID 1 and a larger RAID 5 (120 gb and anywhere from 750 gb to 2 TB, both using hardware RAID). When I installed Proxmox VE it installed onto the RAID 1, but I'd like to mount the RAID 5 as a second LVM and use it as well for VMs. How do I do that?
AFAIK that strange setup is recommended by MS. I suggest to simply use one big RAID10 instead.

- Dietmar
 

cyclones

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May 12, 2009
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We're a RHEL5 and ubuntu shop and setting up your OS on one array and your data on another is something that a lot of admins I know do - that way if one array goes down you only have to restore either your data or your OS and not both.

Also, a RAID 10 isn't really an option since the drive sizes aren't the same between the two arrays, and so that brings me back to my question - can I mount the second array or is Promox just not a solution that will work for us?

I know I can recreate a lot of the functionality using the originating projects (KVM, etc.), but this is definitely the slickest solution I've come across integrating the functionality I need and a few items which just make life easier.
 

dietmar

Proxmox Staff Member
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Apr 28, 2005
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www.proxmox.com
We're a RHEL5 and ubuntu shop and setting up your OS on one array and your data on another is something that a lot of admins I know do - that way if one array goes down you only have to restore either your data or your OS and not both.
Your RAID arrays goes down? They are on the same controller, and only one array goes down? Thats only possible if 2 HDs fails at the same time - how likely is that? just curious.

Also, a RAID 10 isn't really an option since the drive sizes aren't the same between the two arrays, and so that brings me back to my question - can I mount the second array or is Promox just not a solution that will work for us?
no, thats not supported.

RAID5 has very bad performance.

- Dietmar
 

tom

Proxmox Staff Member
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Aug 29, 2006
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We're a RHEL5 and ubuntu shop and setting up your OS on one array and your data on another is something that a lot of admins I know do - that way if one array goes down you only have to restore either your data or your OS and not both.

Also, a RAID 10 isn't really an option since the drive sizes aren't the same between the two arrays, and so that brings me back to my question - can I mount the second array or is Promox just not a solution that will work for us?

I know I can recreate a lot of the functionality using the originating projects (KVM, etc.), but this is definitely the slickest solution I've come across integrating the functionality I need and a few items which just make life easier.
just for your information, the upcoming flexible storage model will allow you to use several local raid volumes - but this makes no sense for Proxmox VE in almost all cases.

but compared to raid10 you get just half write performance with raid5, so this is not the number one choice for virtualization. keep in mind, in 99 % of cases IO is the bottleneck in every virtualization server so you should never make the first wrong decision in the beginning.

what hard drives do you use? cheap sata or reliable sas? or the absolute coolest performers, SSD´s?
 

raqdedicados

Member
Nov 26, 2008
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Tom regarding the performance, what do u think ? can u give me an advice ?

is better to buy 4 SATA2 disks running in raid 10 or 2 SAS disk running at raid 1.

The controller will be the same in both scenarios, perc 6/i, server dell quad core x 2 2.0. 8gb ram

Thanks !!!
 

tom

Proxmox Staff Member
Staff member
Aug 29, 2006
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Tom regarding the performance, what do u think ? can u give me an advice ?

is better to buy 4 SATA2 disks running in raid 10 or 2 SAS disk running at raid 1.

The controller will be the same in both scenarios, perc 6/i, server dell quad core x 2 2.0. 8gb ram

Thanks !!!
If you can get enough storage with Raid1 (two SAS drives) I would prefer this because of access times and better reliability of SAS drives. But if you can get high performance SATA drives (only WD Velociraptor) this is also good - not sure if you can get them into your Dell.

If you go for RAID1, you can also extend this later to RAID10 if you need more space.
 

tog

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Jun 5, 2008
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Leaving aside performance discussion, you can install Proxmox VE on your RAID10 and then put all of your VM data on the large RAID5 if you want so you have your OS and VM data on different arrays like you're used to.

You just have to do some command line stuff to make that happen, prepare the RAID5 with LVM and mount it in place of where the VM data goes.
 

raqdedicados

Member
Nov 26, 2008
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thanks boths for the answers !!! we will buy 4 x 146GB SAS 15k withd raid 10 raid 10 performance is astonish !!
 

cyclones

New Member
May 12, 2009
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tom - we have both sas and sata servers - no SSDs yet (or for a while I'd guess based on budgets).

tog - that's exactly what I was asking, but I wasn't sure where to mount the new lvm.
 

tog

Member
Jun 5, 2008
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The /var/lib/vz mount is where the OpenVZ and KVM data all goes. You'd want to replace that mount with your own.
 

cyclones

New Member
May 12, 2009
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Thanks - that's what I wanted to know. I'll consider our options and figure out what I want to do next.
 

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