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Investigating Problems with Disks
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I'm trying to determine the state of an OWC Aura 4TB FLASH drive using Disk Certify. I'm seeing the first write pass fail at different offsets each time with an error that says the write operation "hung". Because SoftRAID Lite aborts it never does the read verification. (Disk Verify passes, BTW.)
I'm currently running dd from /dev/zero using a block size of 10MB and a count of 390M (which should overrun the drive). Activity Monitor shows write speeds at about 198 to 220MB/s. But dozens of times per hour I see "pauses" that last 29 to 32 seconds and then writes resume.
dd reports nothing and is still running so I must assume the write call that took extra time eventually completed.
What is SoftRAID Lite's write timeout and can it be modified? It would be very interesting if it would wait long enough to proceed (like dd) and then get to the read/verify step to see if the sectors really did write or not.
I've done Tech Support with MacSales on this but it's pretty clearly a script-based system and the person I'm working with has no technical skill.
This drive is the replacement for a previous unit that failed in a different way. I could press for yet another warranty swap but I'd really like a more definitive diagnosis.
Any pointers would be appreciated.
Posted : 14/04/2017 6:46 pm
Its clear you have a second defective unit. We don't have any special tools to help you diagnose this further, the drive clearly has areas on its media that it has a hard time writing to.
Our recommendation is get an RMA for it and not spend further time with it.
Certify does not use the SoftRAID driver and essentially dd replicated your result. Usually with SSDs that are "filled up", the write delays are normal. (writes over used areas on SSD's an be much slower, but 30 second delays are very abnormal.)
If you want to do another test, enable TRIM in the OS and TRIM in SoftRAID. Let the disk sit for a day or so, so TRIM has a chance to write out the areas marked used. Then see if you get the same kind of issues. But I don't think this is productive use of your time, unless you enjoy being an SSD detective here. ;-)
Posted : 17/04/2017 3:02 pm
