To speed up varnish i choosen to cache data to a mdadm raid0 partition on half the drives (rest is raid1).
Create raid0 partitions (done twice)
(parted) print Model: ATA ST2000NC001-1DY1 (scsi) Disk /dev/sda: 2000GB Sector size (logical/physical): 512B/4096B Partition Table: msdos Disk Flags: Number Start End Size Type File system Flags 1 1049kB 1001MB 1000MB primary boot, raid 2 1001MB 1009GB 1008GB primary raid (parted) mkpart Partition type? primary/extended? primary File system type? [ext2]? xfs Start? 1100GB End? 1900GB (parted) set 3 raid on (parted) print Model: ATA ST2000NC001-1DY1 (scsi) Disk /dev/sda: 2000GB Sector size (logical/physical): 512B/4096B Partition Table: msdos Disk Flags: Number Start End Size Type File system Flags 1 1049kB 1001MB 1000MB primary boot, raid 2 1001MB 1009GB 1008GB primary raid 3 1100GB 1900GB 800GB primary raid
mdadm raid0
mdadm -C /dev/md0 -l raid0 -n 2 /dev/sd[a-b]3 mkfs.xfs /dev/md0 mdadm --detail --scan >> /etc/mdadm.conf
fstab
To make sure this server can start evan if the raid0 partition fails, add nofail. noatime is added since atime is not needed for this drive.
/dev/md0 /var/lib/varnish/ xfs defaults,nofail,noatime 0 0
If it fails
If the drive fails varnish will crash, at a reboot varnish will not start (this is because the file varnish want to use dont fit within the root partition. to fix the raid0 partition, recreate all steps it and mount. dont forget to update /etc/mdadm.conf.