SSD Cache
SSD cache can improve the performance of random access by storing frequently accessed data on the SSD cache. SSD cache can be mounted on a volume or iSCSI LUN (Block-Level). There are two types of SSD cache:
- Read-only cache can consist of 1 to 12 SSDs which can be mounted respectively in a basic or RAID 0 configuration to improve the random read performance of the storage space on which it is mounted.
Note:SSD read-only cache stores copies of data from the volume; thus, no data loss will occur even if the read-only cache has crashed.
- Read-write cache can be mounted in a RAID 1 / RAID 5 / RAID 6 configuration, depending on the number of SSDs (up to 12 SSDs), to improve the random read and write performance of the storage space on which it is mounted.
Both types of SSD cache implement an LRU (Least Recently Used) algorithm to swap the data in the cache.
Synology ssd cache compatibility
SSD cache with additional card M2D18:
| Built in NVMe |
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From
Samsung SSD 970 EVO MZ-V7E250BW M.2 2280 NVMe 250GB SSD
|
| M2D18 +NVMe & SATA SSD |
|
From
Intel SSDPEKKA256G701 DC P3100 256GB M.2 NVMe SSD Samsung MZ-V7P1T0 970 PRO 1TB M.2 NVMe SSD Western Digital WDS100T2X0C Black 1TB M.2 NVMe SSD Samsung SSD 970 EVO MZ-V7E250BW M.2 2280 NVMe 250GB SSD |
| M2D18 card +SATA SSD |
|
From
Crucial CT1050MX300SSD4 MX300 1TB M.2 SATA SSD Samsung MZ-N6E2T0 860 EVO 2TB M.2 SATA SSD Western Digital WDS200T2B0B-00YS70 Blue 2TB M.2 SATA SSD
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SSD– A Solid State Drive is a data storage device using integrated circuit assemblies as
memory to store data persistently. This enables a much faster transfer speed than
HDD.
HIT Rate– How often a searched-for item is actually found in the cache. The greater the number of
requests that can be served from the cache, the faster the overall system performance
becomes.
IOPS– Input / Output Operations Per Second, is a common performance measurement
used to benchmark computer storage devices.