> I think the conclusion you've arrived at is not quite accurate. It could be > described more accurately as a possible data corruption issue specific to drbd > and/or the kernel, and trim commands as issued by the TrimTester software. It > appears TrimTester was written to debug a very specific SSD trim issue when > accessing SSDs directly. It would be necessary to look at exactly what > TrimTester is doing to determine if this is a real bug or some anomaly due to > what exactly the software is doing.
I anticipated this objection. That's why I also ran the tests without the part of TrimTester that issues TRIM commands. There are three parts to TrimTester. The main executable just writes tons of data to the device. A separate shell script called trim_periodic.sh issues TRIM commands. And the third part called drop_cache.sh periodically drops the system caches. I ran some of my tests using only the TrimTester executable without the TRIM management pieces, and the results were the same. > If there is an issue it is possible it could be > either in in drbd or the kernel. Just because the issue is present when drbd > is > used does not automatically exclude the problem being in kernel, it may be an > issue that only arises in the kernel when drbd is used. What if you try with > a > newer kernel such as 4.9, would the same corruption occur? I can't disagree with that. What I do know is that the corruption only occurred when DRBD was in the stack, and never when it isn't. I can test with a different kernel, but if it still fails (as seems likely) then we would not have learned anything > Also, would > the specific conditions created by TrimTester ever be reproduced in a real > world scenario, or is it something that will only ever show up when running > TrimTester? I don't know. The source code for TrimTester is in the download, but I don't know C or Linux system calls well enough to answer those questions. According to the TrimTester author, all it does is write a buttload of data to the device and work it hard. -- Eric Robinson _______________________________________________ drbd-user mailing list drbd-user@lists.linbit.com http://lists.linbit.com/mailman/listinfo/drbd-user
