PENNY WATCH

[Street_Gnocca]

IWEB .0001 Performance Boost for Normal Storage
SSDs can also be used to boost the performance of SAS and/or SATA drives by using the SSDs to extend cache and contain a “write index”. The IceWEB Management Console allows SSDs to be assigned as an “L2ARC” which is a level 2 cache which augments main memory cache. If so con?gured, the IceWEB OS will use those SSDs both as a Level 2 cache for reads and writes, as well as extra space for deduplication and virtualization tables. SSDs can also be assigned as the space for the ZFS Intent Log or “ZIL”. The ZIL is a non-volatile index that records all writes until they are committed to disk. All writes to the array will be written ?rst to the ZIL and committed to the application, and then subsequently to disk using a “lazy” update process.
This means that writes get the bene?t of SSD speeds without the cost of having all SSDs for storage. Ultimately you need enough drives to handle the sustained I/O rate from the applications, but tactically this can make a huge positive impact to application performance.