RAID performance

[simonstre]

Presently we use a RAID 5 setup for a DB server (it's an Informix database.) We know that the server lags often and we think that the latency in reading could be in cause. We don't write often, but we constantly read data from it.

Someone suggested that we change to RAID 1.0, but I dunno if it'll have any effect... We already splitted the logs and the data files on two separated disks. Any suggestions?

 

[Onomatopoeic]

Presently we use a RAID 5 setup for a DB server (it's an Informix database.) We know that the server lags often and we think that the latency in reading could be in cause. We don't write often, but we constantly read data from it.

Someone suggested that we change to RAID 1.0, but I dunno if it'll have any effect... We already splitted the logs and the data files on two separated disks. Any suggestions?

As far as performance goes, RAID Level-5 is good for reads, not so good for writes.

Separating the logs from the database by placing each on different physical volumes helps if you have a highly active database.

 

[Handruin]

Is there another application on the server that could be causing interrupts to the bus of some sort? Is the RAID5 in hardware or software? (i'm assuming hardware)

 

[simonstre]

The RAID5 is hardware. No other application interracts with the server, in fact, there's praticaly no other apps on it! We read a bunch of data for each client, and there's almost 70 people here. But what is really weird is that the lack of performance is random; one time, it can take 5 to 10 seconds to retrieve the files from the DB, but 5 minutes later (and still alone in the office!) it takes 30 MINUTES.

:eekers: WTH??? I'm not sure that the RAID5 is in cause here... but you know, the IT guys here have been convinced by the application vendor... I just try to proove that the RAID5 is correct, that we will gain nothing by switching to RAID1.0. Am I right?

 

[Pradeep]

RAID 10 will give you better write speeds, and better reliability (i.e you could lose more than one drive (one drive from each mirror) and the array would still be OK.) But you will have less capacity for a given number of drives, and adding additional capacity is very costly as well.