Linux-geex.com Website Review

recently i’ve acquired some new hardware and i want it to perform as fast as possible. the setup is quite trivial for a home desktop nevertheless i wanted it to excel on io performance as it will be use as my backup server too. a common way to improve performance is by adding a cache system, this applies to many things in it and block devices are no exception. the relevant hardware components for this post are the 7x 2tb drives and 1x nvme card. the setup is not ideal as the models are not all the same, some to perform better than others some are newer and others older. nevertheless  money and storage capacity was important also i wanted to use them anyway. security is also very important, so all the data written to these drives (including the nvme card) must be encrypted. on the other side i want to be able to expand the raid devices when the time comes so i also use lvm, as file system i use you may wonder why didn’t i use a simpler setup with btrfs or zfs? mostly because i wanted to use raid 5 or 6 and on btrfs the stability the nvme device is used both to the os, home, etc, but it does contain a lvm logical volume to be used as cache for the raid device. the insane and i won’t be able to exhaust with my day to day use, so it can spare a few iops to make my backups go a bit faster. i’ve tested bcache and lvmcache, as a benchmark tool i’ve used iozone. i’ve done the tests with 256kb,1mb,8mb block sizes, the test file is 96gb (as it needs to be bigger than the total ram amount 64gb). the initial test was made using the full setup without any caching system, it will be used to set a base of comparison. each test was done with 3 different block sizes 256k, 1mb, 8mb, test settings and cache mode for all the test is “writeback”: in what regards to overall performance the outcome is not as expected. lvm cache really didn’t seem to improve the system performance. in some of the tests it was quite slower than the no cache mdraid and in some other just slightly faster. nevertheless bcache did show real