Hi Len, The only problem with your approach is that if your users created a bunch of 1TB Data Volumes (the default maximum) but put next to no data on them, with overprovisioning set to 1, the system will assume they all have 1TB of data allocated and it could mark the storage as full and prevent its use, even though it has massive amounts of free space.
Regards Geoff Higginbottom D: +44 20 3603 0542 | S: +44 20 3603 0540 | M: +447968161581 [email protected] -----Original Message----- From: Len Bellemore [mailto:[email protected]] Sent: 24 July 2013 13:48 To: [email protected] Subject: RE: storage overprovisioning Hi Geoff, That's a really great explanation. Thanks. One option then is to still use thin provisioning on the storage array, but not put in any kind of overprovisioning factor in Cloudstack. We could then give ourselves a fairly large volume on the array, and defer the monitoring of "real" used space to storage monitoring tools. This would take away the confusion around how storage is displayed in the Cloudstack UI, as it would be displaying "actual" space available, and it would take away any guess work around by which factor I should be overprovisioning in Cloudstack. I would still see the benefits of thin provisioning to my array as a whole, but what is actually available to my Cloudstack users would be a lot more clearly defined. I would not have CS administrators looking at the display in the UI and thinking, "well it says I've got 200GB available, but how much have I really got" Len -----Original Message----- From: Geoff Higginbottom [mailto:[email protected]] Sent: 24 July 2013 09:23 To: [email protected] Subject: RE: storage overprovisioning Hi Len, Some Background: There are two Storage 'measures', the actual storage 'used', and the storage 'allocated'. As an example let's assume you are using NFS, have 100GB of Primary Storage, and have set storage.overprovisioning.factor to 4 Because of the Over Provisioning Factor, your system will report that you have 0GB / 400GB of Primary Storage 'Allocated' and 0GB /100GB 'used' If you now deploy 5 VMs, based on a Template with a 10GB ROOT disk, your 'allocated' storage would now be reporting as 50GB / 400GB of Primary Storage Allocated or 12.5% However, due to the wonders of Thin Provisioning, the ROOT disks for each of the VMs are only currently using 2GB of actual storage, so your 'used' Storage will be reported as 10GB / 100GB or 10 % Now as the VMs get used, data gets added, updates installed etc, the thin provisioned disks will grow, and may now be consuming 6GB of disk space each, and so the 'used' Storage will now be reported as 30GB / 100GB or 35% but the 'allocated' will still be 12.5% As a Service Provider, the 'Allocated' setting is what you bill your clients for, as they have effectively reserved this amount of space, but you need to monitor the 'allocated' to make sure it does get too close to your limits. But from an IT management perspective it's the 'used' Storage amount, which is the real data on disk value which may be more important as this will tell you when you disks are about to fill up. The two Global Settings you originally asked about pool.storage.allocated.capacity.disablethreshold pool.storage.capacity.disablethreshold They simply prevent any more Volumes from being allocated to the Primary Storage when the disable threshold is exceeded, and is measured as a percentage, with 85% expressed as 0.85 They allow you to decide which counter will disable the allocation of new Volumes, 'Allocated' or 'Used' Regards Geoff Higginbottom D: +44 20 3603 0542 | S: +44 20 3603 0540 | M: +447968161581 [email protected] -----Original Message----- From: Len Bellemore [mailto:[email protected]] Sent: 23 July 2013 18:06 To: [email protected] Subject: storage overprovisioning Hi Guys, Was wondering if someone could explain to me the difference between the following Global Settings: pool.storage.allocated.capacity.disablethreshold pool.storage.capacity.disablethreshold Many thanks! Len ________________________________ IMPORTANT NOTICE. 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