On 14/02/17 07:58 PM, John R Pierce wrote: > On 2/14/2017 4:48 PM, tdukes at palmettoshopper.com wrote: >> 1- Better to go with a hardware RAID (mainboardsupported) or software? > > I would only use hardware raid if its a card with battery (or > supercap+flash) backed writeback cache, such as a megaraid, areca, etc. > otherwise I would use mdraid mirroring. > > >> 2 - Can an existing drive with data on it be used as aRAID drive without >> losing current data? > > software mdraid will let you add a mirror to an existing disk. or if > its using LVM, you can mirror in LVM now. Note; If you're mirroring /boot, you may need to run grub install on both disks to ensure they're both actually bootable (or else you might find yourself doing an emergency boot off the CentOS ISO and installing grub later). >> 3 - Can additional drive(s) be added later with a changein RAID level >> without current data loss? > > Only some systems support that sort of restriping, and its a dangerous > activity (if the power fails or system crashes midway through the > restriping operation, its probably not restartable, you quite likely > will lose the whole volume)... with LVM mirroring, you can add more > pairs of drives as additional mirrors to the volume group. > > -- Digimer Papers and Projects: https://alteeve.com/w/ "I am, somehow, less interested in the weight and convolutions of Einstein’s brain than in the near certainty that people of equal talent have lived and died in cotton fields and sweatshops." - Stephen Jay Gould