RAID 1 is supposed to mirror data to a second disk, why hasn’t this happened?
Posted on 2010-11-11
Recently our HP ML115 server’s RAID array became degraded, the array type was a RAID 1 mirror. The RAID consisted of two 500GB SATA disks and were partitioned as C and E. When we booted the server we could see in Explorer we now had an F and G drive listed as well as the original C and E drives, the server was now seeing the two individual disks. F was a replica of C and G was a replica of E. We noticed that some data was missing from the E drive where the company data is stored, but was on the G drive. We can boot the server with disk 1 which contains C and E, but we can’t boot using the second disk. We have since performed tests on the second disk and it is damaged and HP has sent a replacement. Test performed on the first disk indicate that it is good.
Why should the damaged disk have more complete, up to date data although it is damaged, and the good drive has the missing data? We believed that data was immediately mirrored across the disks as it was written, supposedly avoiding this discrepancy. Could someone explain this?