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It's generally agreed upon that defragmenting is beneficial for your mechanical drives but harmful for your SSDs.
How does this come into play when you have a mechanical drive setup with SSD caching?
I'm talking primarily about Intel Smart Response Technology.
This is how SRT works:
You access a block of data for the first time from your mechanical Hard Drive, at which point it is also copied into cache (SSD).
The next time you access that same block, it will be accessed from cache instead.
As you access additional blocks of data from your mechanical Hard Drive, they will also be copied into cache, and accessed from the cache upon subsequent requests for that block.
This process repeats until your cache is full at which point the oldest blocks in cache are pushed out of cache.
Note that I reference "blocks" because SRT works on the block/hardware level, not the file level or the program level. If you have a 3GB file that you only regularly access a few hundred megabytes of, only the blocks that contain those few hundred megabytes of data are likely be cached (as opposed to the whole file)
Until the cache actually fills up, it will continue to cache every single block that you access regardless of how frequently you access it. Only when the cache becomes full does anything start to be pushed out of cache, and at that point it will start with the oldest data in cache, not based on frequency of usage. Of course, anything you use on a regular basis is unlikely to become the oldest data in cache as it becomes the newest data in cache again every time you use that program.
Given the relatively simple method in which SRT caching functions, I would assume that it would try to cache every block that the defrag program accesses during the defrag - likely not desirable.
The alternative would be to disable caching, defrag the mechanical drive, then re-enable caching. In that case however, since significant amounts of data on the disk has been relocated, I would assume that the cache would have to completely start from scratch after that.
Thoughts?
How does this come into play when you have a mechanical drive setup with SSD caching?
I'm talking primarily about Intel Smart Response Technology.
This is how SRT works:
You access a block of data for the first time from your mechanical Hard Drive, at which point it is also copied into cache (SSD).
The next time you access that same block, it will be accessed from cache instead.
As you access additional blocks of data from your mechanical Hard Drive, they will also be copied into cache, and accessed from the cache upon subsequent requests for that block.
This process repeats until your cache is full at which point the oldest blocks in cache are pushed out of cache.
Note that I reference "blocks" because SRT works on the block/hardware level, not the file level or the program level. If you have a 3GB file that you only regularly access a few hundred megabytes of, only the blocks that contain those few hundred megabytes of data are likely be cached (as opposed to the whole file)
Until the cache actually fills up, it will continue to cache every single block that you access regardless of how frequently you access it. Only when the cache becomes full does anything start to be pushed out of cache, and at that point it will start with the oldest data in cache, not based on frequency of usage. Of course, anything you use on a regular basis is unlikely to become the oldest data in cache as it becomes the newest data in cache again every time you use that program.
Given the relatively simple method in which SRT caching functions, I would assume that it would try to cache every block that the defrag program accesses during the defrag - likely not desirable.
The alternative would be to disable caching, defrag the mechanical drive, then re-enable caching. In that case however, since significant amounts of data on the disk has been relocated, I would assume that the cache would have to completely start from scratch after that.
Thoughts?