Corrupt files when performing a redirected restore on a SIS volume

I was recently performing a restore of some old data that had been archived to tape using Symantec Backup Exec 2010. The restore job appeared to complete fine, without any errors or warnings – however when we came to try and use the data, certain files were corrupt/empty – despite the size being correct.

I inspected the contents of the file by opening in an editor – it turned out that all the affected files just contained null/space characters and no real content, as if they had not restored correctly.

I inspected the BackupExec log and saw some entries that gave me a clue to where the problem may lie…

BEREMOTE: [01/06/12 10:41:48] [0000] [56084] 01/06/12 10:41:48 Tag=IO_REPARSE_TAG_SIS, file=example1.pdf
BEREMOTE: [01/06/12 10:41:48] [0000] [56084] 01/06/12 10:41:48 Reparse data not restored during redirection of example1.pdf.
BEREMOTE: [01/06/12 10:41:48] [0000] [56084] 01/06/12 10:41:48 Tag=IO_REPARSE_TAG_SIS, file=example2.pdf
BEREMOTE: [01/06/12 10:41:48] [0000] [56084] 01/06/12 10:41:48 Reparse data not restored during redirection of example2.pdf.

The server in question was running Windows Storage Server 2008 – which provides the Single Instance Store (SIS) service. SIS basically removes duplicate files from your filesystem by taking a copy of the file, then putting symbolic links to the master file.

There are a couple of simple workarounds to the problem…

1) Do not redirect the restore job – just restore to the original location

2) Restore to another drive that does not have the SIS service enabled on it

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