VPLEX: How to Set Rebuild Transfer Size

Summary: This article describes how to increase or decrease the rebuild transfer rate, and the effects of doing this.

This article applies to This article does not apply to This article is not tied to any specific product. Not all product versions are identified in this article.
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Instructions

A REBUILD WILL OCCUR WHEN:

  • Logging failed, mirror is marked as out of date
  • Whenever a new mirror is added to the device, such as a migration
  • Whenever an existing device is marked out of date
  • A distributed RAID 1 has one leg marked out of date due to storage issues or intercluster link issues
  • When a mirror (leg) of a distributed-device is removed from the source

Command to return transfer rate for all devices:

  • VPlexcli:/> rebuild show-transfer-size *

Command to return device name and transfer size.

  • VPlexcli:/> rebuild show-transfer-size --devices *

 

-----------  -------------
ddev_1       2M
ddev_10      2M
ddev_11      2M
ddev_12      2M
ddev_13      2M
ddev_7       2M
ddev_8       2M
ddev_9       2M

Default size: 128k    
Max size: 2M (A size larger than this can lead to host performance issues)
It is recommended this be set to 128KB as a balance between minimal host impact and acceptable rebuild/migration performance.
Generally speaking, using transfer-sizes larger than 2MB has no proven to show significant rebuild time improvement.

Set the transfer-size on a specified device to 1M:

  • VPlexcli:/> rebuild set-transfer-size --devices /clusters/cluster-1/devices/testdevice --limit 1M
  • Alternatively: VPlexcli:/distributed-storage/distributed-devices/DD_1234> set transfer-size 1M

Set transfer size at component level

  • VPlexcli:/distributed-storage/distributed-devices/DD_1234/distributed-device-components/device_Symm1234_1234_1> set transfer-size 1M

Set the transfer-size for all devices to 2M:

  • VPlexcli:/> rebuild set-transfer-size * 2M

Set the transfer-size for all distributed devices to 256k:

  • VPlexcli:/distributed-storage/distributed-devices> set *::transfer-size 256k


Notice if throughput increases after increasing the transfer size - It is not always the case that increasing the transfer rate speeds up the rebuilds.

Additional Information

  • VPLEX rebuild traffic does not do QoS and is not aware of contention /traffic
  • If transfer rate is set too high, it affects performance
  • The rebuild-type should be set to full, and this cannot be set manually
  • If the volumes are thin-provisioned, then the rebuild should be thin
  • If the volumes are thick-provisioned, then the rebuild should be thick
  • The VPLEX chooses the best fit rebuild type, and this cannot be set manually
  • It always tries to rebuild incrementally initially and if this is not possible, then a full rebuild begins

VPLEX has two types of rebuilds: full and logging. 

A full rebuild occurs whenever a new mirror is added to device, such as a migration, or whenever an existing device is marked out of date. 

A logging rebuild occurs when a mirror (leg) of a distributed-device is removed or added from the source, the VPLEX tracks the changes made on the blocks of the source device from the logging volume, and apply these changes to the mirror once it is reattached.

Affected Products

VPLEX Series

Products

VPLEX Series, VPLEX VS1, VPLEX VS2, VPLEX VS6
Article Properties
Article Number: 000158424
Article Type: How To
Last Modified: 26 Nov 2025
Version:  6
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