January 6, 201610 yr I precleared a drive and then added it to the cache pool as the second drive, it had a blue square, I then started the array following the instructions in the manual and was never presented with an option to format, this is my cache device screen: Is this normal? it doesn't seem right to me where is the FS for the second drive?, how do I fix it?
January 6, 201610 yr Community Expert The second cache drive is added to the existing one as a 'cache pool' so there is no need to format it.
January 6, 201610 yr Author OK, I see now it is using both disks and has increased the size, it just looked odd to me. How would I replace the first disk, just like an array disk?
January 9, 201610 yr OK, I see now it is using both disks and has increased the size, it just looked odd to me. How would I replace the first disk, just like an array disk? I would copy all of the info from the disk you want to replace to a user share on the protected array, this step is probably not needed since you have a pool running already and i assuming you let it finish mirroring onto the second cache disk? Then i believe the next step would be to stop the array and scroll down to the Cache disk you want to replace and then add the disk to replace it make sure the file system on the new disk is set to BTFRS, once you pick the disk to replace just start the array... it should then start to mirrior the new disk ... if any global mods want to jump in maybe i missed a step! AJ
March 1, 201610 yr Sorry to bring up an old topic but I have 250 ssd and I just added 2 120ssds to the cache but it's not adding to the over all total cache storage?
March 1, 201610 yr Sorry to bring up an old topic but I have 250 ssd and I just added 2 120ssds to the cache but it's not adding to the over all total cache storage? That's correct. All data is duplicated in a RAID1 pool, so each 120 holds half the contents of your 250, with the extra 10GB not available for storage. You should be seeing a total capacity of 240GB with (1) 250 and (2) 120 drives.
March 1, 201610 yr Sorry to bring up an old topic but I have 250 ssd and I just added 2 120ssds to the cache but it's not adding to the over all total cache storage? That's correct. All data is duplicated in a RAID1 pool, so each 120 holds half the contents of your 250, with the extra 10GB not available for storage. You should be seeing a total capacity of 240GB with (1) 250 and (2) 120 drives. Gotcha thanks for the fast reply! So if I want a bigger cache I need to upgrade the 250?
March 1, 201610 yr Go to http://carfax.org.uk/btrfs-usage/, select RAID-1, change number of devices at the top to indicate how many drives you want to use, change the sizes of each drive to what they are, and see what the total space for files shows.
March 1, 201610 yr Community Expert Sorry to bring up an old topic but I have 250 ssd and I just added 2 120ssds to the cache but it's not adding to the over all total cache storage? That's correct. All data is duplicated in a RAID1 pool, so each 120 holds half the contents of your 250, with the extra 10GB not available for storage. You should be seeing a total capacity of 240GB with (1) 250 and (2) 120 drives. Gotcha thanks for the fast reply! So if I want a bigger cache I need to upgrade the 250? No that definitely won't do it. See the calculator page jonathanm linked. Basically what it does is makes sure you have 2 copies of everything, and each copy has to be on a separate drive. So if you have 2x120, and one other drive larger than that, the 2x120 together can hold one copy, so the other copy can only be 240. It doesn't matter how much larger you make the other drive those 2x120 will limit you to 240.
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