On Tue, Dec 7, 2010 at 3:02 PM, Chris Mason <chris.mason@xxxxxxxxxx> wrote: > Excerpts from Jon Nelson's message of 2010-12-07 15:48:58 -0500: >> On Tue, Dec 7, 2010 at 2:41 PM, Chris Mason <chris.mason@xxxxxxxxxx> wrote: >> > Excerpts from Jon Nelson's message of 2010-12-07 15:25:47 -0500: >> >> On Tue, Dec 7, 2010 at 2:02 PM, Chris Mason <chris.mason@xxxxxxxxxx> wrote: >> >> > Excerpts from Jon Nelson's message of 2010-12-07 14:34:40 -0500: >> >> >> On Tue, Dec 7, 2010 at 12:52 PM, Chris Mason <chris.mason@xxxxxxxxxx> wrote: >> >> >> >> postgresql errors. Typically, header corruption but from the limited >> >> >> >> visibility I've had into this via strace, what I see is zeroed pages >> >> >> >> where there shouldn't be. >> >> >> > >> >> >> > This sounds a lot like a bug higher up than dm-crypt. ÂZeros tend to >> >> >> > come from some piece of code explicitly filling a page with zeros, and >> >> >> > that often happens in the corner cases for O_DIRECT and a few other >> >> >> > places in the filesystem. >> >> >> > >> >> >> > Have you tried triggering this with a regular block device? >> >> >> >> >> >> I just tried the whole set of tests, but with /dev/sdb directly (as >> >> >> ext4) without any crypt-y bits. >> >> >> It takes more iterations but out of 6 tests I had one failure: same >> >> >> type of thing, 'invalid page header in block ....'. >> >> >> >> >> >> I can't guarantee that it is a full-page of zeroes, just what I saw >> >> >> from the (limited) stracing I did. >> >> > >> >> > Fantastic. Now for our usual suspects: Maybe not so fantastic. I kept testing and had no more failures. At all. After 40+ iterations I gave up. I went back to trying ext4 on a LUKS volume. The 'hit' ratio went to something like 1 in 3, or better. I will continue to do testing with and without LUKS. I did /not/ reboot between tests, but I do start with a fresh postgres database. -- Jon -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
