Tunesys after adding new disk enclosure

[shang83]

Hi,

I'm new to this tunesys. Here's my scenario, I have a 3PAR 7400 2 node controller with 2 disk enclosure. All the 72 disk slot are accupied with 900GB sas disk. A single CPG with raid 5 and set size 3+1 HA magazine was used. 

After I added a new disk enclosure with 24 900GB sas disk. HP advice me to change the CPG HA from magazine to cage and perform tunesys. This is because I could only see the about 1.6TB free space in CPG if I changed HA from magazine to Cage. If I remain the HA in Magazine, the CPG would have 18TB.  

The tunesys have been run for a day and have not complete. Could I perform creation of new Virtual volume when the tunesys is still running? This is because I need to create a new virtual volume for the file server for migration. 

Does the 3par management console have option to stop the tunesys? Or should I stop the tunesys and switch back the CPG to Magazine? 

[Gary_L]

Tunesys Will run in the background, and start up additional tasks that take care of the rebalancing of data and any data layout changes.  You can still continue to build virtual volumes and manage the array as normally would.

Ensure you are using your new CPG at the new availability level for any new volumes.

Gary

[shang83]

Would there be any degrade in performance, i/o and data lost?

[shang83]

_{The tunesys have been runing for 1.5 days. I found out on the first day, after running the tunesys the cpg have 8TB free capacity, but I check again 6 hours later the cpg only have around 5.5TB. Why the CPG free capacity increase and decrease?} 

_{I'm worried I would not get the Free capacity desired for the purpose to purchase additional disk enclosure.} 

[Gary_L]

Hi Shang83,

Tunesys will run in the background from days to possibly a week or more.  A lot has to do with the amount of space available to move data and the structure of the change, (i.e. just releveling data or releveling and changing raid levels).

During the tunesys process you will see variations of space usage from more space being used to the ultimate goal of realizing the free space at teh completion of the tune.

Also, to answer your earlier question, there will be no IO or data loss during a tunesys process.  You will have some backend overhead as data is moving, additional disk IO for instance.  The effect of this is typically nominal but monitoring performance on a regular basis should provide you an indication if there is any visible effect.

Gary

[shang1983]

Tunesys is now at 80% completion. I receive alert about the allocation disk percentage reached above 75%. I checked in IMC it is now 78%. Is this normal when performing tunesys? Would the allocated disk percentage reduce after tunesys complete?