Promise Pegasus R6 & Mac Thunderbolt Reviewby Anand Lal Shimpi on July 8, 2011 2:01 AM EST
The Pegasus: Quirks
I did encounter occasional glitches with the Promise Utility. No show stoppers, but annoying nonetheless. Sometimes when deleting a logical drive I'd get an error telling me that the delete operation failed (even though it didn't):
Refreshing the logical drive page revealed that the drive had been deleted, despite the warning.
Sometimes various fields will be populated with not a number (NaN) instead of the actual data itself. Just as before, refreshing the page in question usually cleared the problem:
The Pegasus itself was most problematic when operating at or near its capacity. In one case I tried filled a 10TB RAID-5 array with 10TB of data. Rather than copy a bunch of large files over and over again, I used Iometer to generate a single 10TB file on the drive. Somewhere around the 9TB marker Iometer stopped writing to the drive. Mac OS X reported a single 10TB file on disk but the actual file was under 9TB in size leaving over 1TB of free space on the drive. I force quit Iometer and tried writing to the drive manually. At this point the drive became incredibly slow to respond. I tried canceling the copy but Finder crashed under OS X. The Pegasus itself actually hung and refused to power down, I had to pull the plug on the device in order for it to power cycle. When I plugged it back in the R6 wouldn't appear under OS X. I had to pull two drives to break the RAID-5 array then delete/recreate the array to get it working again. Of course I lost all of the data I wrote to the drive, thankfully it was just a bunch of repeating bytes created by Iometer. I attempted the same thing again (twice) and couldn't duplicate the issue. I'm going to assume this was an Iometer related issue (or a problem with creating a single ~9TB file on the array), but it's worth disclosing regardless.
The only other time I had an array go bad was when I swapped in four SandForce SSDs and created a giant RAID-0 array. One of the drives simply dropped out of the array, forcing me to delete and recreate the array. As I mentioned earlier, I can't be entirely sure if this is a Promise issue, SandForce issue or a little of both. I never had a drive mysteriously disappear when using the Hitachi drives that came with the Pegasus however.
Other than the issues I've mentioned here, I didn't encounter any problems during my testing of the Pegasus R6.