Managing disk space on a VM host

larsen161

I've built out a decent size NVR server on a 12 disk LFF, DL180 G6 and thinking about how I manage the disk space as it grows. I have a single RAID volume that I've created on the server and allocated 30GB initially for the OS and thinking I add storage in 1TB chunks as needed to the recording volume. The server is going to be used for other VMs so allocating all the space at once doesn't work.

The virtual disks are all using LVM so growing these for either the OS or storage will be done by adding additional logical volumes. I've setup a server in Rackspace like this and attached new block storage volumes to the server as disk space requirements grew. It seems to work well and haven't had any issues in 1yr of running that server doing it this way.

Are there any nuances to configuring the LVMs now anticipating them growing as time goes on? Any other words of advice for managing storage in a situation like this?

scottalanmiller

@larsen161 said:

The virtual disks are all using LVM so growing these for either the OS or storage will be done by adding additional logical volumes.

Wouldn't LVM mean that you could avoid doing that? Adding additional volumes you can do without LVM. LVM will make it so that you can continue to grow the existing volume and keep it all one space without needing the application to be aware that anything has changed.

scottalanmiller

@larsen161 said:

Are there any nuances to configuring the LVMs now anticipating them growing as time goes on? Any other words of advice for managing storage in a situation like this?

Use XFS

larsen161

@scottalanmiller
Maybe I didn't explain it correctly or I'm not sure what you mean...

From what I understood in order to resize a volume you need to shutdown the host: http://support.citrix.com/article/CTX120865
Not what I want to do.

On the Rackspace server, I just add each 1tb volume (1tb is max storage you can add at a time) to the host as needed and then add that live into the volume group for the video storage. the application isn't away of any changes and continues to write to that same space. This is all that I did...

fdisk /dev/xvdx
  t
  8e
  w
mkfs -t ext4 -c /dev/xvdx1
pvcreate /dev/xvdx1
vgextend VolGroup00 /dev/xvdx1
lvextend -l +100%FREE /dev/VolGroup00/data 
resize2fs /dev/VolGroup00/data

larsen161

@scottalanmiller hmm, something new to learn. reading through this now: http://lwn.net/Articles/476263/

scottalanmiller

@larsen161 said:

@scottalanmiller
Maybe I didn't explain it correctly or I'm not sure what you mean...

From what I understood in order to resize a volume you need to shutdown the host: http://support.citrix.com/article/CTX120865
Not what I want to do.

On the Rackspace server, I just add each 1tb volume (1tb is max storage you can add at a time) to the host as needed and then add that live into the volume group for the video storage. the application isn't away of any changes and continues to write to that same space. This is all that I did...
fdisk /dev/xvdx
  t
  8e
  w
mkfs -t ext4 -c /dev/xvdx1
pvcreate /dev/xvdx1
vgextend VolGroup00 /dev/xvdx1
lvextend -l +100%FREE /dev/VolGroup00/data 
resize2fs /dev/VolGroup00/data

that's different than what you originally described which was making new LVs. You don't make a new LV, you just extend the existing one. Which is what you are showing here.

scottalanmiller

@larsen161 said:

@scottalanmiller
Maybe I didn't explain it correctly or I'm not sure what you mean...

From what I understood in order to resize a volume you need to shutdown the host: http://support.citrix.com/article/CTX120865
Not what I want to do.

That's not at all related. That's for resizing the SR on a XenServer host, nothing to do with resizing an LV when you add another device to a VG.

scottalanmiller

@larsen161 said:

@scottalanmiller hmm, something new to learn. reading through this now: http://lwn.net/Articles/476263/

http://mangolassi.it/topic/8029/linux-common-filesystems

We've talked about XFS here in ML quite a bit in the last two months,