Re: [ovirt-users] Maximum storage per VM?

[Yaniv Kaul]

On Tue, Oct 10, 2017 at 3:31 PM, Dmitri Chebotarov <dcheb...@gmu.edu> wrote:

> Good Morning
>
> I'm using virtio-scsi (also tried virtio), not using IDE (doesn't IDE have
> 4 devices limit? it's long time since I used IDE...).
>
> This is for servers hosting own/nextCloud and Samba for a small/medium
> groups with large datasets (60-80TB) per server.
>
> If ovirt-scsi allows to attach >20 disks  then it meets my needs in this
> case. Thank you.
>
> The reason I opted for LVM is performance. It's so much faster with LVM
> and striped volumes compared to a single large disk. I'm seeing very high
> 'iowait' numbers (to the point when VM is unresponsive) when I'm dumping
> large amount of data to a single disk. But with LVM striped volumes
> 'iowait' at around ~20% and I can get to ~750MB/s in the same environment
> (same config with single disk is ~160MB/s).
>

Interesting. What version of Gluster are you using? Are you using sharding?
What's the underlying storage for Gluster and how is it set up?


>
> Also, healing a single large disk on gluster takes ages (I'm using erasure
> coded volumes) .
>

Sharding and newer versions of Gluster should help here.
Y.


>
>
> Thank you,
> --
> Dmitri Chebotarov.
> George Mason University,
> 4400 University Drive,
> Fairfax, VA, 22030
> GPG Public key# 5E19F14D: [https://goo.gl/SlE8tj]
>
>
> 
> From: Yaniv Kaul <yk...@redhat.com>
> Sent: Tuesday, October 10, 2017 4:03:08 AM
> To: Dmitri Chebotarov
> Cc: users@ovirt.org
> Subject: Re: [ovirt-users] Maximum storage per VM?
>
> On Fri, Oct 6, 2017 at 10:24 PM, Dmitri Chebotarov <dcheb...@gmu.edu
> <mailto:dcheb...@gmu.edu>> wrote:
> Hello
>
> I'm trying to find any info on how much storage I can attach to a VM.
>
> Is there a recommended/maximum for number of disks and maximum disk size?
>
> Disk count depends on the interface - IDE - very few, virtio- 20-something
> (depends on the number of PCI slots available), virtio-SCSI - more.
> What is the use case?
>
>
> I'm using GlusterFS as backend storage for the cluster.
>
> The VM uses LVM (/w striped volumes) to manage attached disks.
>
> Aren't you having layers over layers over layers? Is that the optimal
> arrangement?
> (Again, would be interesting to understand the use case to better provide
> information).
> Y.
>
>
> Thank you,
> --
> Dmitri Chebotarov.
> George Mason University,
> 4400 University Drive,
> Fairfax, VA, 22030
> GPG Public key# 5E19F14D: [https://goo.gl/SlE8tj]
>
> ___
> Users mailing list
> Users@ovirt.org<mailto:Users@ovirt.org>
> http://lists.ovirt.org/mailman/listinfo/users
>
>
___
Users mailing list
Users@ovirt.org
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Re: [ovirt-users] Maximum storage per VM?

[Dmitri Chebotarov]

Good Morning

I'm using virtio-scsi (also tried virtio), not using IDE (doesn't IDE have 4 
devices limit? it's long time since I used IDE...).

This is for servers hosting own/nextCloud and Samba for a small/medium groups 
with large datasets (60-80TB) per server.

If ovirt-scsi allows to attach >20 disks  then it meets my needs in this case. 
Thank you.

The reason I opted for LVM is performance. It's so much faster with LVM and 
striped volumes compared to a single large disk. I'm seeing very high 'iowait' 
numbers (to the point when VM is unresponsive) when I'm dumping large amount of 
data to a single disk. But with LVM striped volumes 'iowait' at around ~20% and 
I can get to ~750MB/s in the same environment (same config with single disk is 
~160MB/s).

Also, healing a single large disk on gluster takes ages (I'm using erasure 
coded volumes) .


Thank you,
--
Dmitri Chebotarov.
George Mason University,
4400 University Drive,
Fairfax, VA, 22030
GPG Public key# 5E19F14D: [https://goo.gl/SlE8tj]



From: Yaniv Kaul <yk...@redhat.com>
Sent: Tuesday, October 10, 2017 4:03:08 AM
To: Dmitri Chebotarov
Cc: users@ovirt.org
Subject: Re: [ovirt-users] Maximum storage per VM?

On Fri, Oct 6, 2017 at 10:24 PM, Dmitri Chebotarov 
<dcheb...@gmu.edu<mailto:dcheb...@gmu.edu>> wrote:
Hello

I'm trying to find any info on how much storage I can attach to a VM.

Is there a recommended/maximum for number of disks and maximum disk size?

Disk count depends on the interface - IDE - very few, virtio- 20-something 
(depends on the number of PCI slots available), virtio-SCSI - more.
What is the use case?


I'm using GlusterFS as backend storage for the cluster.

The VM uses LVM (/w striped volumes) to manage attached disks.

Aren't you having layers over layers over layers? Is that the optimal 
arrangement?
(Again, would be interesting to understand the use case to better provide 
information).
Y.


Thank you,
--
Dmitri Chebotarov.
George Mason University,
4400 University Drive,
Fairfax, VA, 22030
GPG Public key# 5E19F14D: [https://goo.gl/SlE8tj]

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Users mailing list
Users@ovirt.org<mailto:Users@ovirt.org>
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Re: [ovirt-users] Maximum storage per VM?

[Yaniv Kaul]

On Fri, Oct 6, 2017 at 10:24 PM, Dmitri Chebotarov  wrote:

> Hello
>
> I'm trying to find any info on how much storage I can attach to a VM.
>
> Is there a recommended/maximum for number of disks and maximum disk size?
>

Disk count depends on the interface - IDE - very few, virtio- 20-something
(depends on the number of PCI slots available), virtio-SCSI - more.
What is the use case?


>
> I'm using GlusterFS as backend storage for the cluster.
>
> The VM uses LVM (/w striped volumes) to manage attached disks.
>

Aren't you having layers over layers over layers? Is that the optimal
arrangement?
(Again, would be interesting to understand the use case to better provide
information).
Y.


>
> Thank you,
> --
> Dmitri Chebotarov.
> George Mason University,
> 4400 University Drive,
> Fairfax, VA, 22030
> GPG Public key# 5E19F14D: [https://goo.gl/SlE8tj]
>
> ___
> Users mailing list
> Users@ovirt.org
> http://lists.ovirt.org/mailman/listinfo/users
>
___
Users mailing list
Users@ovirt.org
http://lists.ovirt.org/mailman/listinfo/users

Re: [ovirt-users] Maximum storage per VM?

[Dmitri Chebotarov]

Hi Kasturi

The data disks are located on a stand-alone Gluster cluster, 
distributed-dispersed volume.
Is there a limit in this case?
I tested with up to 8x3TB disks and everything looks good so far. I'm trying to 
find out what's the maximum supported disks count and size w/o actually 
creating/attaching disks.

I cannot find the info in oVirt/RHEV docs...

Thank you,
--
Dmitri Chebotarov.
George Mason University,
4400 University Drive,
Fairfax, VA, 22030
GPG Public key# 5E19F14D: [https://goo.gl/SlE8tj]



From: Kasturi Narra <kna...@redhat.com>
Sent: Monday, October 9, 2017 7:59:34 AM
To: Dmitri Chebotarov
Cc: users@ovirt.org
Subject: Re: [ovirt-users] Maximum storage per VM?

Hi Dmitri,

  If the vms are created on a Hyperconverged setup then the max disk size  
recommended is 2TB.

Thanks
kasturi.

On Sat, Oct 7, 2017 at 12:54 AM, Dmitri Chebotarov 
<dcheb...@gmu.edu<mailto:dcheb...@gmu.edu>> wrote:
Hello

I'm trying to find any info on how much storage I can attach to a VM.

Is there a recommended/maximum for number of disks and maximum disk size?

I'm using GlusterFS as backend storage for the cluster.

The VM uses LVM (/w striped volumes) to manage attached disks.

Thank you,
--
Dmitri Chebotarov.
George Mason University,
4400 University Drive,
Fairfax, VA, 22030
GPG Public key# 5E19F14D: [https://goo.gl/SlE8tj]

___
Users mailing list
Users@ovirt.org<mailto:Users@ovirt.org>
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Re: [ovirt-users] Maximum storage per VM?

[Kasturi Narra]

Hi Dmitri,

  If the vms are created on a Hyperconverged setup then the max disk
size  recommended is 2TB.

Thanks
kasturi.

On Sat, Oct 7, 2017 at 12:54 AM, Dmitri Chebotarov  wrote:

> Hello
>
> I'm trying to find any info on how much storage I can attach to a VM.
>
> Is there a recommended/maximum for number of disks and maximum disk size?
>
> I'm using GlusterFS as backend storage for the cluster.
>
> The VM uses LVM (/w striped volumes) to manage attached disks.
>
> Thank you,
> --
> Dmitri Chebotarov.
> George Mason University,
> 4400 University Drive,
> Fairfax, VA, 22030
> GPG Public key# 5E19F14D: [https://goo.gl/SlE8tj]
>
> ___
> Users mailing list
> Users@ovirt.org
> http://lists.ovirt.org/mailman/listinfo/users
>
___
Users mailing list
Users@ovirt.org
http://lists.ovirt.org/mailman/listinfo/users

[ovirt-users] Maximum storage per VM?

[Dmitri Chebotarov]

Hello

I'm trying to find any info on how much storage I can attach to a VM.

Is there a recommended/maximum for number of disks and maximum disk size? 

I'm using GlusterFS as backend storage for the cluster.

The VM uses LVM (/w striped volumes) to manage attached disks.

Thank you,
--
Dmitri Chebotarov.
George Mason University,
4400 University Drive,
Fairfax, VA, 22030
GPG Public key# 5E19F14D: [https://goo.gl/SlE8tj]

___
Users mailing list
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