Fat to Thin & Thin to Fat Converstion
No we aren’t talking about a revolutionary new diet! It’s the ability to take a fat volume and turn it into a thin volume or vice versa!
The steps taken for a Fat to Thin conversion are:
- Create a System Thin Provisioned Virtual Volume
- Place a temporary block on the Full Virtual Volume
- Move User Space into the Thin Provisioned Virtual Volume
- Unblock the Full Virtual Volume
- Start region mover to copy data from the LDV to the Thin LD (same as Online copy)
- Convert the Full Virtual Volume to a Thin Provisioned Virtual Volume
The steps for Thin to Fat are the same as above. So I won’t repeat myself.
You may have noticed that blocks are placed on the virtual volumes, so how it data written? Well when a conversion is initiated writes are cached, however there has to be a start and stop block, which can cause a temporary disruption of I/O. I haven’t tested this but it is meant to be transparent to the users.
If for some reason you have a system failure e.g. power outage then the conversion is not automatically restarted.
Windows Server 2012
It seems that Windows have followed on from VMware and have introduced ODX (Offload Data Copies) which offloads copies to the 3PAR StoreServ in a similar way to VAAI.
Perhaps the coolest new feature of Windows Server 2012 is that it has T10UNMAP command built in for Thin Provisioning space reclamation. So no more sdelete!
Calvin Zito (twitter handle @HPStorageGuy) has an excellent demo which can be found here on YouTube
System Reporter 3.2
System Reporter in my opinion was always a pain to install. It was pretty complex and it always took me a couple of attempts to get it working. One of the really cool things with 3PAR OS 3.1.2 is that it’s been built in!
The only thing you need to do is run one of the following commands to create the .srdata Virtual Volume
The On Node System Reporter sits on the Non Master Node, if this fails then it continues on remaining nodes Non Master Nodes. Yes that’s right you need to have a four node system to benefit from this.
Adaptive Optimization (scheduled block tiering) is actually included in 3PAR OS 3.1.2 meaning it has no dependency to the On Node System Reporter. However, a couple of things to note:
- If using an external System Report, Adaptive Optimization will not work with 3PAR OS 3.1.2
- Off Node Adaptive Optimization is no longer supported
Data sampling intervals for performance statistics are High (5 minutes), Hourly and Daily, these are non configurable.
Logical Disk Region access rate data for Adaptive Optimization is sampled every 30 minutes, again this is non configurable.
Something to note, there is no migration of data migration for System Reporter. Meaning you will loose all previous performance metrics.
With the new System Reporter we get some new CLI commands which are
• srcpgspace—Space reports for common provisioning groups (CPGs)
• srldspace—Space reports for logical disks
• srpdspace—Space reports for physical disks
• srvvspace—Space reports for virtual volumes (VVs)
• srrgiodensity—Region I/O density reports for CPGs or Adaptive Optimization configurations
• sraomoves—Space report for Adaptive Optimization moves
• srhistld—Histogram performance reports for logical disks
• srhistpd—Histogram performance reports for physical disks
• srhistport—Histogram performance reports for ports
• srhistvlun—Histogram performance reports for VV LUN exports (VLUNs)
• srstatcmp—Performance reports for cache memory
• srstatcpu—Performance reports for CPUs
• srstatld —Performance reports for logical disks
• srstatpd—Performance reports for physical disks
• srstatport—Performance reports for ports
• srstatvlun—Performance reports for VLUN