Date: Fri, 31 Jan 2014 13:11:47 +0200 From: Antonis Anastasiadis <anastasiadis@datalive.gr> To: freebsd-fs@freebsd.org Subject: ZFS - Uncompress raw LZ4 data Message-ID: <52EB84F3.50602@datalive.gr>
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Hi everyone, I'm trying to recover a deleted file from a single disk LZ4 compressed dataset. The pool is in fine condition. I tried printing the uberblock history via zdb, but the file had been deleted before the oldest uberblock I could find. So I guess I can't roll back into that pool state. The file was very small (90-120 kb) so it should fit in a single ZFS block. I do not know the deleted block's DVA in order to restore it via zdb -R. But I have similar files on the disk, so I can get the file header. As a last resort, I'm thinking going brute force and somehow find all ZFS blocks (even deleted ones) from the raw partition, decompress the data and check the binary data for the file header. Is there a tool that decompresses raw LZ4 data out there? Max Bruning has written a utility called "zuncompress" but it doesn't support LZ4 (http://mbruning.blogspot.gr/2009/12/zfs-raidz-data-walk.html) I know 'm shooting in the dark here, but I would appreciate any other ideas from the ZFS gurus out there. Thanks, Antonis Anastasiadis
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