We're looking at use two SSD in a software RAID 1 raid on CentOS. We have tested performances and it is the same as a SSD alone.
But we fear that because of mdadm, lifetime of the SSD will shorten. Here is the warning of Redhat team :
Red Hat also warns that software RAID levels 1, 4, 5, and 6 are not recommended for use on SSDs. During the initialization stage of these RAID levels, some RAID management utilities (such as mdadm) write to all of the blocks on the storage device to ensure that checksums operate properly. This will cause the performance of the SSD to degrade quickly.
If mdadm write on all the disk on initial check seems OK, but how does it check thereafter ?