Upon completion of this course you should be able to:
Course Prerequisites:
None
Students are expected to have a working knowledge of:
N/A
1. Introducing SSD Caching
2. Setting Up SSD Caching
3. Removing SSD Caching
4. Notes
SSD caching has two modes: Read/Write and Read-Only. If using one SSD, then Read Only mode is the only option. Read/Write mode is available in addition to the former if two or more SSDs are installed.
Different modes will be automatically created into corresponding RAID configurations according to the number of SSDs. In Read-Only mode, RAID 0 will be created automatically with more than two SSDs. In Read/Write mode, two SSDs will be set to RAID 1, three SSDs will create RAID 5, and four SSDs will set up RAID 10 for caching.
Capacities vary with the RAID level used. RAID 0 combines the capacity of all drives. RAID 1 uses half of the available capacity for storage while the other half is a mirror. RAID 5 uses all but one drive’s worth of capacity.
Read-Only mode:
Your NAS will take frequently accessed data and copy it to installed SSDs.
Read/Write mode:
Reading from read/write mode is identical to read only mode.
Read/write mode adds the ability to write data directly to SSDs from a client. Since SSDs are faster than hard drives, write performance to a NAS with read/write SSD caching enabled is usually higher.
SSD caching has a number of applications where its advantages can most easily be taken advantage of.
Note: Small files are files smaller than 1 MB.
Please check below items before setting.
Step 1
Step 2
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Step 4
After an accelerated drive is created, the icon for a volume will change to reflect its status.
SSDs that are part of an accelerated drive must be safely removed before removing them from a NAS or performing other types of maintenance, like a RAID upgrade or capacity upgrade.
Click SSD Caching under Management to view cache usage and read hit rate. The higher the hit rate, the higher the efficiency.
Some forms of maintenance require an SSD cache drive to be removed. If migrating to a new NAS, upgrading RAID levels, upgrading capacity, or simply no longer in need of SSD caching you will need to safely remove the SSD cache.
Inside Storage Manager, click a volume, click Management and open SSD Caching.
To remove SSDs from an accelerated volume, click Safely Remove SSD Cache. Your NAS cannot be powered off while SSDs are being safely removed. If your NAS powers off or otherwise is interrupted, it is possible for data loss to occur. After completion, you may remove SATA SSDs or power down the NAS to remove M.2 SSDs.
Listed below are the RAM capacity requirements for various sizes of SSD cache drives on an ASUSTOR NAS device.
For example, if you want to use a cache size of 4 TB for caching on a Lockerstor 4 Gen2, it will requires 1820 MB of RAM. RAM used for SSD cache may only occupy up to a quarter of total memory capacity, which means the minimum required total RAM size is 8 GB. This also means that the aforementioned Lockerstor 4 Gen2, which comes with 4 GB of memory as standard, needs to be upgraded to 8 GB to use the full 4 TB SSD cache.