October 12, 20169 yr I've tried to search for this, and hope I haven't missed anything obvious, but I just rebuilt my unRAID system and added a cache drive. Everything went reasonably well, but after setting up the cache drive it immediately filled up with data from my data drives. I haven't copied anything new to the system yet, but the cache drive seems to be constantly churning, as if it is moving data off from the data drives to the cache drive, and then back to the data drives. Is there some sort of automatic re-balancing of my data drives that's causing this, or is there something else going on? How can I control this behavior? Thanks!
October 12, 20169 yr Community Expert The only thing that should ever cause data be moved from the array drives to the cache drive is if you have a share set as "Use Cache: Prefer" and then mover starts up.
October 13, 20169 yr Author Yeah, I totally misunderstood what the Prefered cache setting for the shares does. I expected the Cache settings to only affect new files copied to the array. Going back and re-reading the help, I now see that it says (for Prefer) "When the mover is invoked, files and subdirectories are transfered off the array and onto Cache disk/pool". I misread that because I never considered a use-case for copying files from the array to the cache for long term storage.
October 13, 20169 yr Community Expert Yeah, I totally misunderstood what the Prefered cache setting for the shares does. I expected the Cache settings to only affect new files copied to the array. Going back and re-reading the help, I now see that it says (for Prefer) "When the mover is invoked, files and subdirectories are transfered off the array and onto Cache disk/pool". I misread that because I never considered a use-case for copying files from the array to the cache for long term storage. The normal reason for using this setting would be when you do not currently have a cache disk but intend to add one later.
October 13, 20169 yr Author Yeah, I totally misunderstood what the Prefered cache setting for the shares does. I expected the Cache settings to only affect new files copied to the array. Going back and re-reading the help, I now see that it says (for Prefer) "When the mover is invoked, files and subdirectories are transfered off the array and onto Cache disk/pool". I misread that because I never considered a use-case for copying files from the array to the cache for long term storage. The normal reason for using this setting would be when you do not currently have a cache disk but intend to add one later. I must be having a serious density issue at the moment, because that still doesn't make sense to me. Now that I know that this functionality exists, the only thing I can think of would be to move data to a faster drive for performance reasons (database, etc.), especially avoiding parity overhead during write operations.
October 13, 20169 yr I must be having a serious density issue at the moment, because that still doesn't make sense to me. Now that I know that this functionality exists, the only thing I can think of would be to move data to a faster drive for performance reasons (database, etc.), especially avoiding parity overhead during write operations. Expand (database, etc.) to for example VM and especially Docker (and space related to dockers with lots of I/O). That should cover the most common cases.
Archived
This topic is now archived and is closed to further replies.