Which RAID to use
Sharkster
Sharkster
61517946
shar...@sharkster.org
Jan Eric Andersson
> Which RAID is better for use in my FTP RAID linear, RAID 0 or RAID 1
Depends on what you want and what kind of drives you have.
If you want safety, use RAID-1, which mirrors one disk onto another. This
results in half the storage space of both drives combined, but gives you
security,. as both drives contain the same data.
If you want capacity and are not as concerned about data security[1], use
RAID-linear (if you are using IDE disks) or RAID-0 (if you are using SCSI
disks). These options give you the capacity of both drives added together,
but at the cost of no backup.
RAID-linear has the advantage that you can use dissimilar drive sizes, but
does not stripe (interleave) the data over both disks - it fills up one,
then continues on the other. This is safer than RAID-0 (which does stripe
the data), as if you have a full array and one drive fails, you will still
have the data from the other drive.
Using RAID-0 on IDE disks makes very little sense, unless they are on
seperate controllers, due to the single tasking nature of the IDE bus. Only
one IDE unit on a controller can be active at any given time, so striping
can actually be slower than accessing one disk - you write a bit to one
disk, then the other has to seek to the right spot on the drive, then you
write a bit to that disk, then back to the first for another bit, etc.
On SCSI systems, however, striping disks can lead to a noticable
performance increase, as the SCSI bus does multitask, allowing several
devices to be written to or read from simultaneously.
Jan Eric
[1] I'm using "security" here in the sense of minimizing data loss in case
of hardware failure, not in the sense of any added protection against
hacking.