Will my data safety be jeopardized by the use of SSD cache?

Details

SSD cache will not increase the risk of data loss as long as it is properly configured. We highly advise you to assess your situation and select the SSD cache types and RAID configurations that best suit your needs. We also suggest that the maximum drive fault tolerance of the SSD cache also be arranged as such.

Resolution

Read-only cache

There will be no risk of data loss if a read-only SSD cache crashes.

When this type of SSD cache is used, only frequently accessed data will be stored in the SSD cache to increase the random read speed. Data modifications are performed directly to the HDDs, just like a native volume.

Read-write cache

If a read-write cache is used, there may be a risk of data loss if the number of SSDs degraded exceeds the tolerance of the RAID configuration used. Data loss may also occur if the data stored in the cache has not been written back to the HDDs if an SSD degrades.

A read-write cache writes random data into SSDs first to speed up data access and writes data back to the HDD in the background. To ensure data safety when a read-write cache is enabled on the Synology Unified Controller, we recommend building at minimal a RAID 1 configuration using at least two SSDs (this provides at least one drive fault tolerance).

Notes:

Synology provides an automatic protection mechanism when a read-write cache degrades to enhance data safety. Refer to this article for more details.
A RAID 1 read-write cache consisting of two SSDs provides a one drive fault tolerance. If users need a higher level of security, we recommended using more SSDs and building RAID 1/RAID 5/RAID 6/RAID 10 for a higher level of fault tolerance.

Further reading

Bu yazı yardımcı oldu mu?

Evet ／ Hayır