software raid and hardware raid

[Waugh]

Dear All,

Why hardware raid performance better than software raid.
Second thing is how the raid card is connected to raid group any one have diagram on it.

Regards
Rkumar

[marsh_1]

hardware raiding is faster generally as all the overhead involved in maintaining and using the raid sets is taken care of by the raid controller the server operating system just has to request the data , with software raid all that has to compete with everything else going on on the system.
on your second point if you mean physical connection for a raid card it is just like a normal scsi adapter in your server but with a raid controller built in , so a scsi cable from the raid card to either an internal or external storage shelf.

HTH

[Ted Buis]

Which RAID card do you have? Are you using it with internal disks? If so, what is the server model? If you are using it with external disk enclosures, what are those models. There are many HP Smart Array controller cards. Old versions tend to be SCSI and newer ones are SAS. Many ProLiants have built-in RAID Controllers for internal disks, and some have the option for connection to external disk enclosures. Battery Backed Write Cache (BBWC) is a big plus for performance since it can acknowledge a write as complete as soon as it hits the cache rather than waiting until it has been written to the magnetic disk which is always much slower. Therefore software RAID will often be much slower than hardware RAID with a BBWC even if the processor didn't need off-loading.