Can we connect two raid controllers in standby?

Rishabh Gupta

11/16/22, 9:00 AM

I'm new to server machines and even even installing raid controllers, so pardon me if its too basic question.

We have a SuperMicro X10DRH-I Motherboard connected to a raid controller AOC-S3108L-H8Ir, both are supermicro products. We need to add one more raid controller in hot/cold standby with this controller.

My doubt is is this even possible and if possible how?

If not possible then a general question say if the current raid controller fails how can we recover the data, since data can be stored in any any hardisks given the controller is configured in RAID6, is recovering 100% data possible safely with surety?

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raid

hardware-raid

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Server

Simon Richter

11/16/22, 9:53 AM

That's a normal LSI/3ware/Avago MegaRAID controller card, with SuperMicro branding.

If the card itself breaks, you replace it with another MegaRAID card. The configuration is stored on the disks, so you can restore arrays on the new card, this is a manual process though as there is a safety mechanism and the card requires confirmation before it will access disks that were initialized on another controller.

It is difficult to provision a standby, as most of the failure modes for the controller itself are not wear related, so the chance of the "standby" card failing first is rather high. I'd probably look into building a separate system and setting up replication.

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Rishabh Gupta

11/16/22, 10:22 AM

so it means we can always recover the data when the controller gets failed? and if so can we use other controller if not of same type to do so?

Simon Richter

11/16/22, 10:26 AM

@RishabhGupta, you should be able to use any controller from the MegaRAID family that has the required connectors, but you should verify that with Broadcom. The remaining failure modes should be handled with [backups](https://serverfault.com/questions/2888/why-is-raid-not-a-backup).

Rishabh Gupta

11/16/22, 10:52 AM

thanks for the help!

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Server

Dmitry Nosachev

2/8/23, 1:14 PM

Hot standby was possible with MegaRAID Syncro CS RAID controllers (two controllers connected to dual-expander backplanes and SAS drives), but they were discontinued several years ago.

As for cold standby, Simon Richter is right. You can use any 3108 based controller from Supermicro (except AOC-S3108L-H8IR-16DD if you have more than 16 drives, as this controller is limited to 16 drives maximum) or 3108 based or newer controller from Broadcom: 9361 or 9460. Broadcom's latest 9560 series controllers are also backwards compatible, but have different connector — Slimline x8 instead of SFF-8643, so you will have to change the cables as well.