I have a new 8TB Seagate Archive disk in one of my machines (Ubuntu 14.04.2, Kernel 3.19 from git.freedesktop.org, MSI 7817, Haswell chipset, i5-4570 CPU) and there are multiple issues with this disk. See also here.
First, every now and then the disk times out and becomes completely inaccessible under large write loads (see log below). If I umount it when this happens I get a kernel oops. As long as it does work, its write performance (tested with
rsync) is very irregular and jumps between 180MB/s for a second, then between 12MB/s and 40MB/s and then to several seconds doing nothing (while the disk LED is constantly lit).
On average I get about 30MB/s write performance out of this disk, which is disappointing. Read performance does not seem to suffer.
1. Is this normal? The disk has Seagates new "shingled" tracks that require rewriting adjacent tracks when changing data on one track. Update: According to answers below, the answer would be "Yes". The disk design makes write performance somewhat unpredictable if you write more than ~15GB at a time.
2: How do I avoid the crashes and SATA timeouts? I have changed cables, disk location in my PC case, cable routing in the case, used "noncq" and "acpi=off" and various other kernel parameters, none of these solved the issues completely. Even increasing the SATA timeout for this disk did not avoid the problem 100% (although it made it occur less often).
[Kernel messages, debug info and some text removed since the question was downvoted. I assume this is because it was too long. Thank you for removing the downvote. :)]