Does the PCS distribution support SSDs and the TRIM mechanism of SSDs?
Since kernels of PCS are based on kernels of RHEL 6.x, there is TRIM support as outlined in the documentation.
There are different setups with SSD disks.
Setting up the system on SSD disks.
TRIM support should be enabled if OS partition is located on SSD drive using the appropriate mount option.
The purpose is the following. File deleting happens in a file system all time, but the information related to the deleted file only kept in OS, not to a device. As a result, a device treats both valid data and invalid data (deleted file) in its storage media the same way, all necessary operations keeping data alive are applied. For example, background defect management and error recovery process are used for HDD. Merge, wear leveling and erase are applied to SSD. OS’s process, such as format, Defragger, Recycle bin, temp file deleting and Paging can produce a considerable amount of deleted file. By telling device the deleted file information as invalid data, the device can reduce its internal operation on all invalid data as self-optimization.
Using SSD in Parallels Cloud Storage for caching and journalling.
If SSD is used for Cloud Storage cluster, due to the specifics of the data, placed on the SSD drive in our case, TRIM becomes next to useless, as PCS does not remove any data from the SSD partition - it keeps the same cache and journal files permanently on it.
Storing virtual environments on SSD.
In this situation there is minimum amount of files created and deleted, the file system is almost static. However the content of files is changed constantly. There is almost no chance to issue
discardoperation for TRIM.