Low Performance of Reading/Writing Large Files on LUNs Due to LUN Property Errors

Publication Date:  2012-07-22 Views:  171 Downloads:  0
Issue Description

The performance is low when reading/writing two large files on the same LUN, and the remaining time of copy operation keeps growing or invisible on the AS.

Product and version information:
  • S2600
  • S5000 series
Alarm Information
None
Handling Process
  1. Wait until the background formatting completes for the LUN.
  2. Set the write policy to Write back for the LUN.
Root Cause
  1. In the ISM, open the Properties dialog box for the faulty LUN.
  2. It is found that the LUN is either running background formatting, or the write policy of the LUN is set to "Write through".

Conclusion:

  • The LUN is either running background formatting or its write policy has been set incorrectly, causing the low performance when reading/writing large files concurrently on the LUN.
Suggestions
Take measures as suggested below to avoid this problem:
  • Make sure the background formatting has been completed for the LUN before reading/writing large files concurrently.
  • Set the write policy to Write back for the LUN.

The processing performance of storage devices can be deteriorated when the background formatting is ongoing or setting the write policy to Write through.

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