Hardware
Hi,
I recently replaced our aging Compaq server with an IBM eServer. My question is: What is the advantage/benefits of having a Mirrored Hard Disk and Hard Disk with RAID (This is a Domain and a File Server).
Thanks and regards,
Minhaj.
Hi,
Mirroring IS Raid. Raid 1 in fact.
Raid 0 : Striping - the data is distributed evenly across all disks in the raid set.
Benefits : Speed.
Disadvantages : One disk crashes and you lose the lot.
Raid 1 : Mirroring - the data is duplicated across two disks
Benefits : Faster read speed. Redundancy - one disk fails, the system continues.
Disadvantages : Slower writing speed. More expensive - you need two 20Gb disks to get 20Gb woth of storage.
Raid 3 : Striping with parity - the disk is spread across 3 or more disks with one disk being allocated as the "parity disk".
Note: Raid 5 is the same as 3 but with the parity information spread evenly across all disks.
Benefits : Speed. Raid 5 is even better with its speed as all three disks are evenly utilised to get the data rather that two. Higher disk utilisation than mirroring. Disk space = Number of disks - 1. Redundancy - any one disk fails, the system continues.
Disadvantages : Speed decreases when one disk fails as the data has to be reconstructed from the parity information.
Raid 5 is the choice for most people as it offers the benefits of speed and redundancy with only a moderate added expense of one extra disk required for the parity information. You need at least three, though.
Always do raid in hardware. Never use software based raid as its way too CPU intensive.
Cheers,
Tim.
by minhajlk
Hi Tim,
Thanks for your info.
Regards,
Minhaj.
by minhajlk
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