Hello,
I am starting to build High Availability system and now I am choosing the storage device. I am not familiar with SANs at all.
I see there are Dual active RAID controller SANs.
I still don't get how can I use such machine in HA system. In my thoughts what I imagine is to connect half of the disks to the first RAID controller in RAID 0, the second half to the other controller in RAID 0 and to make RAID 1 between controllers.
Tell me if this is how such devices should be used.
The model I am looking is QSAN XS3212D-EU
Thank you in advance

What you listed is an all flash storage array. The RAID levels and LUN provisioning is done within the array rather than at server level. That is to say you don't use md or other software RAID tools (i.e. Oracle's ASM) for redundancy because the redundancy exists with the array.

Typically you would present the array LUNs to the server over dual paths in the server itself (i.e. two fiber channel ports or two 10 GB ethernet ports so you have redundant paths at server level such that if one goes down the other can still see the LUNs.

To achieve this you use a software at server level such as Linux native multipath or array vendor provided software such as EMC PowerPath. Multipathing software gives a single name to be used when it sees 2 or more disks (LUNs in the case of an array) are the same one (e.g. you might have 2 paths such as /dev/sdc and /dev/sdg showing up as individual devices and have a name such as /dev/mpath3 as the one name that comprises them both).

The array you listed has 2 "controllers" each with their own ports for path redundancy (vs LUN redundancy). You would ideally configure at least 1 port on both controllers to your ports on the server. In the case where you have 2 such ports from the 2 controllers to 2 separate ports on the server you're actaully presenting 4 paths to the OS (e.g. /dev/sdc, /dev/sdg, /dev/sdk, /dev/sdo) but would still configure your multipathing software at server to present that as one name such as /dev/mpath3.

You can have multiple LUNs from the array presented to each host so you might have /dev/mpath1, /dev/mpath2, /dev/mpath3, etc... depending on how you set it up.

Note that it is normal to use SAN FC switches or dedicated ethernet (ideally 10GB or above) switches between the array and the servers for additional redundancy.