Parity drives on a dedicated controller

[mattm1121]

Greetings,

 

I currently have my SATA drives on the local MB and a 3Ware raid card. I have an extra 3Ware raid card and was wondering if putting the Parity drive(s) on their own controller would help with performance. 

 

Can anybody provide any information if this would be beneficial?

 

Thanks

 

[trurl]

RAID controllers are NOT recommended. No reason to expect separate controller would help performance unless it allows you to get rid of port multipliers.

[mattm1121]

26 minutes ago, trurl said:

RAID controllers are NOT recommended. No reason to expect separate controller would help performance unless it allows you to get rid of port multipliers.

 

I'm not sure I understand this. According to the Unraid documentation 3Ware is listed as a controller brand that is considered compatible;

 

"3Ware AMCC RAID Controller 9550SX-12SI"

 

I have the 3Ware AMCC RAID Controller 9650-24. Am I misinterpreting this somehow? Although the 3Ware itself is not a recommended card all the other LSI RAID cards are. Can you clarify your recommendation?

 

Thanks

 

[trurl]

8 minutes ago, mattm1121 said:

According to the Unraid documentation

Maybe you are looking at old information.

 

Some RAID controllers can be flashed to IT mode, which allows them to treat each disk separately without the hack of making each disk a single RAID0. Those are OK when flashed to IT mode.

 

RAID controllers often don't pass SMART data so Unraid can monitor drive health, don't pass disk serial number which is the preferred way to keep track of disk assignments, might affect partitioning so a disk is presented with a nonstandard size that can cause problems when trying to assign as parity since parity must be at least as large as the largest data disk, maybe other reasons I don't remember.