SSD Cache*
SSD cache can be installed and mounted in a RAID 0 configuration to boost the read speed of a volume, including iSCSI LUN (Regular Files) on a volume, or iSCSI LUN (Block-Level) on your Synology NAS. SSD cache implements a LRU (Least Recently Used) algorithm and write-around cache policy.
Note:
Please check the following before purchasing or installing any SSD cache:
- Refer to the compatibility list at Synology official site to see what SSD cache are supported on your Synology NAS.
- Both SSD cache must be the same model and same size.
- SSD cache requires a certain RAM/cache ratio. Mounting larger SSD cache might require upgrading the memory of your Synology NAS. Cache configurations with 2 x 256-512 GB SSD require upgrading memory to 16 GB.
SSD Cache Info
This section includes the following three sections:
- Mount On: Mount or remove SSD cache on a volume or iSCSI LUN (Block-Level).
- Hit Rate: Displays SSD cache hit rate with a range of 0-100%. Cache hit rate represents the efficiency of your SSD cache. For example if cache hit rate is 50%, that means there is a 50% chance a read operation will be served by the SSD cache.
- Status: Displays the RAID status of a SSD cache mounted on a volume, including iSCSI LUN (Regular Files) on a volume, or iSCSI LUN (Block-Level). This section also shows hardware information, notifying the user if SSD cache are incompatible, or if SSD cache are not identical.
To mount SSD cache:
- Find the drop-down menu, and select the volume or iSCSI LUN (Block-Level) on which you wish to mount the SSD cache.
- Click Mount SSD Cache.
Note:
Data on the SSD cache will be erased. Make sure no important data will be deleted.
To remove SSD cache:
Click Remove SSD Cache.
Note:
- When mounting or removing SSD cache, the system will stop all related services (e.g. shared folders, installed packages, current connections, etc.)
- If any SSD within the cache fails, please remove the cache, and replace the failed SSD. Then remount the cache.
SSD Device Info:
This section displays information regarding SSD cache installed on your Synology NAS, including size, model, S.M.A.R.T. status, and compatibility.
Synology may update the SSD compatibility list in the future. Please remember to periodically update the compatibility list on your Synology NAS by clicking Check compatibility.
File Access Statistics
This section allows you to calculate and view the total size and number of recently accessed files on a specific volume. This information can be referenced when evaluating how much SSD cache is suitable for your system.
To calculate and view file access statistics:
File access statistics can be calculated and viewed with the following three items:
- Volume: Select a volume for calculation.
- Calculate: Click this button to begin totaling the size and number of recently accessed files on the selected volume. Calculation time varies depending on your individual environment. Once calculation is complete, results can be viewed by clicking the Results button.
- Results: Displays the most recently calculated file access statistics of the selected volume, including the number and total size of files which have been accessed within the past seven days.
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*Only available on certain models.