SSD Cache
187
SSD read-write cache needs data protection, so it usually uses RAID 1 or RAID 10 level to
create the SSD cache storage space. Our SSD read-write cache technology uses NRAID 1+
which is parallel NRAID with mirror.
Figure 10-5
SSD Read-write Cache with NRAID 1+
RAID 10 creates a striped set from a series of mirrored drives. The same, adding pair disk
drives into RAID 10 needs to re-stripe the data. So it is hard to add SSDs into SSD cache
pool.
Compare to the RAID 10, NRAID 1+ places the independent block distributed on the different
SSDs but mirror. This NRAID 1+ technology has the data protection and better random I/O
than RAID 10. It also has the advantage of easy to add SSDs into the SSD cache pool to
increase the capacity. In this case, we disallow the SSDs to be removed from the SSD cache
pool because it has the risk of losing write cache data.
If one SSD failure occurs in the SSD cache pool, the status of the SSD cache pool will be
changed to degrade. It will stop write cache and start flushing write cache data into HDDs.
At this time, read cache data still working but no more new read cache data into SSD cache
pool. The SSD read-write cache pool can be set SSDs as dedicated hot spares to prevent
SSD cache pool failure. After inserting an SSD as a hot spare, the SSD read-write cache pool
will be rebuilt until it is completed. And then it reverts to SSD read-write cache service.
Содержание XCubeSAN XS5224D
Страница 71: ...SANOS User Interface 49 nnnnn RPM Power Supply Local PSU n status Reset to Default Yes No...
Страница 99: ...System Settings 77 Figure 6 14 System Information...
Страница 315: ...Monitoring 293 Figure 13 5 Hardware Monitoring...
Страница 327: ...Support and Other Resources 305 Figure 15 1 Download Service Package in the SANOS UI...
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