Datastore space

[just_larry]

I created a data store the size of the vm going in it, I can’t power on the vm that I moved to the new data strore, I get error “Insufficient disk space on datastore ''. I used 95 percent of the data store.

This datastore will only have this one VM ever in it. The VM takes up 330 Gig. How much extra space do I need to have in a datastore for esx4 to be happy.

If I thin provision the VM (330 gig full ) it would only be 120 gig. the snapshot file and swap will fit in a 335 gig data store but is this dangerous? When the database grows at some point it will have this same error.

I read all I could find. I created a new data store of 500 gig for the datastore and all works, I just hate wasting SAN space if I don’t need to. Is there some rule for space that works for all ? What is the safe limits.

I need this VM in its own datastore so the SAN will replicate the LUN over the

[ShaneWendel]

You will need at least the size of all your VMDKs, +the size of the VMs memory for a swap file, +another GB or so (to be safe) for all the various other config and log files.

That's if you don't plan on using snapshots, and if you do, you will need to figure out how much extra space you need (I'd say at least 10% more), which will depend on how long you plan to keep each snapshot around (shouldn't be more than 72 hours ideally) and what kind of change traffic you get to your virtual disks.

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Shane Wendel

VCP: vSphere 4

VCP: VI3

[golddiggie]

You never want to have a VM files using more than 90% of the VMFS's size. You've exceeded that when thick provisioning the VM on the small datastore.

I would advise against making the datastores JUST the size of a single VM's files. You have the ability to make the VMFS datastores up to 2TB-512B in size. On the iSCSI array in use at my last position (two Dell EqualLogic arrays, grouped to give us about 13TB of usable space) I had a couple of 1TB datastores, some 375GB datastores, one 60GB datastore (the ISO library repository, no VM's were to ever go there) and then I filled the balance with 500GB datastores. I set the snapshot allocations on each to use the balance of space (often using 100% of the size, but not going below 50%).

I would make the datastores large enough to house at least a few VM's and then carve the storage up as even as possible. Keep in mind any VM's that might need large storage allocations, and make the datastore large enough to handle that, and still not hit the 90% allocated ceiling. If you're concerned about not "wasting" SAN space, then use thin provisioning for everthing. Keep in mind, there could be VM's that you'll need to convert back to thick provisioning (for performance of the datastore).

VCP4

[vmroyale · Accepted solution]

Hello.

This datastore will only have this one VM ever in it. The VM takes up 330 Gig. How much extra space do I need to have in a datastore for esx4 to be happy.

As with most things, it depends. There are some guidelines for sizing available in Eric Siebert's "[Determining the right size for your VMware VMFS data stores|http://searchvmware.techtarget.com/tip/0,289483,sid179_gci1350469_mem1,00.html]"

If I thin provision the VM (330 gig full ) it would only be 120 gig. the snapshot file and swap will fit in a 335 gig data store but is this dangerous? When the database grows at some point it will have this same error.

It seems that the overallocation of free space is the root of this problem. If you are only using 120 GB, then why has almost 3x that space been allocated? You could cut this to 2x, size the LUN smaller and still come out ahead of where you are right now. Is there a legitimate need for all of this free space?

I read all I could find. I created a new data store of 500 gig for the datastore and all works, I just hate wasting SAN space if I don’t need to. Is there some rule for space that works for all ? What is the safe limits.

Keep growth in mind. Things like snapshots, memory changes, etc can all cause your space requirements to change very quickly.

Good Luck!

[just_larry]

I always used large datastore size, but we now have 4 lefthand boxes for offsite replication and the lefthand boxes will do the replication by lun to lun. I only want to replication on a couple of VMs all at differant times.