https://wiki.archlinux.org/index.php/RAID https://www.zdnet.com/article/chunks-the-hidden-key-to-raid-performance/ http://www.righteoushack.net/device-or-resource-busy-when-using-mdadm/ # MD RAID # no thanks to low end ide hardware raid maybe autodetected sooner or later yum remove dmraid && reboot lsblk ls /dev/md* ? mdadm --stop /dev/md... https://superuser.com/questions/603481/how-do-i-reactivate-my-mdadm-raid5-array gdisk -> partitions to fd00 e.g. for i in /dew/sd{a..d} /dev/sd{f..i} ; do gdisk $i ; done for i in /dev/sd{a..d}1 /dev/sd{f..i}1 ; do dd if=/dev/zero of=${i} bs=128k count=3200 status=progress; done cat /proc/mdstat mdadm --stop /dev/md... # for raid 5 (more space, less advanced level) mdadm -C /dev/md127 -c 16 -l 5 -n 8 /dew/sd{a..d}1 /dev/sd{f..i}1 # for raid 6 and one spare e.g. mdadm -C /dev/md127 -c 16 -l 6 -n 7 /dev/sd{b..h}1 --spare-devices=1 /dev/sdi mdadm --examine --scan > /etc/mdadm.conf # keep waiting while sleep 10; do awk '/%/{printf " %s\r", $4}' /proc/mdstat; done # watch temperatures while : ; do echo $(for i in /dev/sd{a..i}; do echo -n "$i "; smartctl -A $i | awk '/^194 /{print $10}'; done); sleep 60; done > /var/log/temperatures & tail -f /var/log/temperatures # remember to format mkfs.ext4 /dev/md127 # update /etc/fstab -- e.g. /dev/md127 /srv ext4 defaults 1 2 # avoid systemd mdadm.service error, add at least some e-mail address vim /etc/mdadm.conf - MAILADDR user@localhost - # https://www.centos.org/forums/viewtopic.php?t=62007 # check config systemctl start mdmonitor systemctl status mdmonitor # lsblk -f # smartctl -h for i in /dev/sd?; do printf "\n%9s\n" $i; smartctl -a $i | awk '/^M|^ 5|^ 9|^19[78]/{printf "%-25s %8s\n", $2, $NF}'; done # lsblk -f -i | cut --complement -c 52-90 == ca 2 TB storage area ready for testing :) === # e.g. collection of 100 000 "images" mkdir -p -v {0..9}/{0..9}{0..9} for i in ?/??; do pushd $i; for j in {0..99}; do dd if=/dev/urandom of=$(printf "%02d.raw" $j) bs=1024k count=14 status=none; done; popd; done # system stability vs quietness vs overheating? while sleep 10; do sensors | \grep ^[CM].*C\)$ for i in /dev/sd{a..i}; do echo -n "$i " smartctl -A $i | awk '/^194 /{print $10}' done echo done # NEXT WHAT? add naive md5sum database for noticing changed bits some test suites and custom test emulating lightroom / darktable image collection operations, save tests rebuild and rerun with raid6 lvm raid with dm integrity https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/configuring_and_managing_logical_volumes/assembly_configure-mange-raid-configuring-and-managing-logical-volumes#using-dm-integrity-with-raid-lv_configure-manage-raid add deduplicating and compressing https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/deduplicating_and_compressing_storage try ceph ? http://docs.ceph.com/docs/master/ try swift ? https://docs.openstack.org/swift/