To fight random reads, StarWind uses a combination of RAM and Flash
as multi-layered cache, thus achieving major performance increase.
To fight the random writes issue, a different approach is used: StarWind coalesces multiple smaller random writes into a single sequential big write I/O. StarWind allows to achieve up to 90% raw sequential write performance at the file system level, which is by order of magnitude better as compared to conventional file systems (i.e NTFS, ZFS, etc), which is around 10%. This technology, called Log Structuring,
is used in StarWind LSFS that stands for Log-Structured File System.
LSFS brings unique features and functionality to the primary VM-centric storage system:
- Performance is significantly boosted by converting random writes into the fully sequential. Thus the typical VM workload dominated by 100% random I/Os will no longer be the bottleneck of the system`s performance.
- Ability to effectively use parity and striped RAIDs (RAID0, RAID 4, RAID4DP, RAID5, RAID6 etc.), since read-modify-write sequence is no longer used and all spindles of striped array are processing the writes at the same time. This is achieved by writing only big blocks to the disk, thus covering multiple stripes.
- Flash Friendly: StarWind prolongs life of all flash which decreases the CapEx and OpEx. This is achieved by decreasing the number of erase cycles, as the result of aggregating multiple small writes into one massive write, so there is no spots burns. Combined with Space Reduction technologies (In-line Deduplication, On-The-Fly Compression, etc.), it reduces amount of actual data written. As a result, the Flash wearout is reduced.