Hi everyone,
One thing I keep coming across is sizing application specific datastores.
Scenario
Whenever an application requires a dedicated disk, we normally created a dedicated datastore for it. The challange or debate always comes on how big should the lun be. For a normal OS datastore we always leave 20% free as recommended and best practice, for snapshots etc. Now if an application (i.e. SQL Server) needs a dedicated disk like 100GB, our storage would allocate 102GB (17GB X 6 spindles). After VMFS takes partition blocks we would be left with 101GB and then create a 100GB to the guest.
On I have seen some warnings in the logs about "No space for journal on volume xxxxxxx. Opening volume in read-only metadata mode with limited write support"
I found the following KB
http://kb.vmware.com/selfservice/microsites/search.do?cmd=displayKC&externalId=1010931
1) Is there a guide on how one should size such application specific disks, more specially how much free space should be left?
2) Is this issue resolved\removed in vSphere 5?
Thanks