I have an Adaptec 6805 with 7 3TB Hitachi 7200rpm disks in RAID 6 (Win 7x64, i3-2100, 8GB RAM, just a storage box no other tasks). 6-8 TB empty space still and updated to the latest firmware and storage manager software.
Reads are as good as ever, but over the past few weeks writes have slowed to a crawl, like 20MB/s. All disks and the array indicate optimal status from the boot screen and storage manager software.
It sure seems to me like a disk is bad, just hard to figure out since they all are listed as optimal.
Any ideas on troubleshooting this?