Cachecade Pro 2 0 Keygen 33
Christal Rasband
Other vendors have adopted similar technologies; HP SmartArray controllers have their SmartCache. Adaptec has MaxCache... Not to mention a number of software-based acceleration tools (sTec EnhanceIO, Velobit, FusionIO ioTurbine, Intel CAS, Facebook flashcache?).
Coming from a ZFS background, I make use of different types of SSDs to handle read caching (L2ARC) and write caching (ZIL) duties. Different traits are needed for their respective workloads; Low-latency and endurance for write caching. High capacity for read.
If you leave the write caching feature of the controller enabled, the NVRAM will still be used primarily. The SSD write cache will typically only be used for larger quantities of write data, where the NVRAM alone is not enough to keep up.
This depends on how often your writes are actually causing the SSD write cache to become necessary... whether or not your drives are able to handle the write load quickly enough that the NVRAM doesn't fill up. In most scenarios I've seen, the write cache gets little to no action most of the time, so I wouldn't expect this to have a big impact on write endurance - most writes to the SSDs are likely to be part of your read caching.
It doesn't look like any monitoring tools are available for this as there are with other SAN implementations of this feature set... And since the CacheCade virtual disk doesn't get presented to the OS, you may not have any way to manually monitor activity either. This may just require further testing to verify effectiveness...
Speaking about hardware solutions I found no way to know exact hit ratio or something. I believe there are 2 reasons for that: the volume behind controller appears as a single drive (and so it should "just work"), and it is hard to count "hits" which will be not for files but rather for HDD sectors so there'll may be some hit rate even on empty HDD which may be confusing. Moreover algorithms behind "hybridisation" are non-public so knowing hitrate won't help much. You just buy it and put it to work - low spendings (compared to pure SSD solution), nice speed impact.
"Buy it and use it" approach is pretty good thing to consider, but the fact is noone knows for sure how to build the fastest combination: should we use several big HDD and several big cache SSD, or should we use many small HDD and several big SSD etc., and what's the difference between 100 or, say, 500 Gb or 2000Gb of SSD cache (even 500 looks overkill if volume hot data are small-sized), and should it be like 2x64Gb or 8x8Gb to have data transfer paralleled. Again, each vendor uses its own algorithm and may change it on next firmware update.
I write this mostly to say that my findings given me strange answer: if you use some general-purpose and general-load-profiled server, then h/w hybrid controller is fine even with relatively small SSDs, but if your tasks used to be specific you'd better go for s/w solution (which you'll be able to choose since you're the only one who knows the load profile) or for some high-priced PCI-card storages.
In terms of IOPS, their numbers seem to be on par. I tend to keep DiskSpd reports from various servers, and if I scale one of the reports I have to the spindle count I have in the cachecade server, I should only get about 750k IOPS. However, in testing this server i was getting over 2M. It was really the only time I've seen cpu load as a factor by the diskspd threads start to be a factor. Usually cpu is still minimal when the disk starts capping out but that was not the case here. I am kicking myself for not running diskspd with and without but oh well.
The other factor here is it is totally transparent...spend a few hundred bucks on a smaller enterprise class ssd, add it as a cachecade volume and you're done. If you've got money to burn on all-ssd storage then it doesn't matter, but for breathing life into physical spindles, I do consider it worth it.
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