TRIM

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 What is TRIM?

TRIM is a command that enables an operating system to inform an SSD that some blocks of data, such as deleted files, are no longer used and can be wiped internally. The TRIM command is used in the ATA standard, while in SCSI it is known as UNMAP or DISCARD. 

 How to use TRIM in OnApp?

You can enable TRIM for LVM data stores that use SSDs or have Thin Provisioning configured. You can enable TRIM at the Edit Data Store page on your Control Panel or via API. After you enable TRIM, the TRIM related updates are run on a new virtual server during booting. To apply TRIM to the existing virtual servers, rebooting is required.

 What are the requirements for TRIM on Xen?
  • A virtual server is built on Linux, is not a shadow DRaaS instance, and is not built from an ISO or OVA image. 
  • A disk filesystem is ext4 or xfs.
 What are the requirements for TRIM on KVM?
  • A virtual server is built on Linux, is not a shadow DRaaS instance, and is not built from an ISO or OVA image. 
  • A virtual server template uses VirtIO.
  • A disk filesystem is ext4 or xfs and a disk bus type is SCSI.
  • A CentOS version is 7 or later and a KVM version is 1.5.0 or later. 
 What are the events that trigger TRIM during the VS boot or reboot?
  • The TRIM option was updated for a data store. 
  • A disk was assigned to a virtual server.
  • A disk assigned to a virtual server undergone some changes, for example, IO limits were edited.
  • A disk was hot or cold migrated to a data store where TRIM is enabled.
  • A virtual server with a disk was hot or cold migrated to a data store where TRIM is enabled.