How much free space should be reserved in a datastore

[TheVMinator]

I have been using 1TB datastores and preserving 20% of them as free space to prevent them from running out of space.  However now we are moving to larger datastores, 2TB and 4TB.  How should I think about free space reservations as my datastores grow larger?  As they grow larger, is the same percentage still applicable?  20% of 4TB is 800GB - is this overkill?

[admin]

As the size increases we could decrease the free space size percentage ie for 4TB is 10% should be good enough when you keep your snapshots checked.

Thanks,

Avinash

[TheVMinator]

thanks

[Abhilash Basavarajaiah]

I would say 20% because if you run at 10% free space you will run into alerts there by default defined in vCenter and all your datastores will glow red with alerts. Or you could change the values of the alerts if you have storage space constraints.

Also as Avinash said, keep a check on snapshots and also see if you can reserve memory for guests which will save the swap space they use.

[TheVMinator]

Ok thanks.  It does seem that when you get to a certain size, 3TB, 4TB, or at some point, 20% may be too much.  I'm wondering someone has put together a chart of recommendations such as:

1 TB - 20%

2TB - 18%

3TB - 15%

4TB - 12%

6TB - 10%

?

[Abhilash Basavarajaiah]

We always maintain standard LUN sizes in our environment and we have all of them 1TB LUNs so we follow the first rule

1TB - 20%.

Yeah if you go higher it makes sense to spare lesser space or you will end up wasting too much space.