Automatically Reclaim Unused Free Space on HP 3PAR SAN

How HP 3PAR Thin Persistence Benefits from PerfectStorage Space Reclamation

A popular method to reclaim space for the HP 3PAR SAN, as well as other SANs, is to go through a series of mostly manual and labor-intensive steps. The reasons to reclaim the space are clear — it helps eliminate storage inefficiencies that result from file deletions, which saves money otherwise spent in additional storage capacity.

It is typical for large, several hundred GB files to be created and deleted. But when deleted, the 3PAR or other SAN does not know that space is now available, which leads to the multi-step process. Simply, here are the steps taken that recapture the space. A typical scenario for administrators is to use the SDelete (Secure Delete) command line utility to recover space. SDelete deletes existing files and erases any file data that exists in the unallocated portions of a disk (including files that you have already deleted or encrypted). With SDelete, you can also overwrite the contents of free space on your disk.

An alternative to SDelete for recovering space for SANs, including HP 3PAR, is PerfectDisk’s Zero Fill. Different from recapturing space for thin-provisioned disks, defragmentation is not necessary here because the SAN can use the space even if fragmented.

With SDelete

  1. Shut down applications and services that may require disk space.
  2. Run SDelete command line manually to zero out all free space on drive.
  3. Restart applications and services.
  4. Repeat steps 1 – 3 for all drives.
  5. Run appropriate hypervisor migration tool (e.g. VMotion, Live Migration, XenMotion).
  6. Maintain script code and repeat above procedure at regular intervals.

With PerfectDisk Zero Fill

  1. With a single click, consolidate free space and move all files to the beginning of the drive.
  2. Run appropriate hypervisor migration tool (e.g. VMotion, Live Migration, XenMotion).
  3. If desired, set up an automated schedule to regularly move files to the beginning of the disk and zero fill space.

PerfectDisk Zero Fill – the simple, powerful and automated alternative to SDelete. Smarter.

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Category: PerfectDiskStorage