I'm testing a media server backing up its own mounts.  8 mounts at ~100Gb
writing to four LTO with an MPX of 2.  The disk storage involved can take
data faster than four drives can give it.  The data is in large
multi-gigabyte files.  I'm using iostat to watch the drives.

Backup, filesystem-level full: Drives write at ~30MB/sec, total time about 2
hours.
Backup, raw volume full: Same as filesystem full, maybe 5% faster
Restore, filesystem-level full: Drives read at ~30MB/sec, total time is
about 2.75 hours
Backup, raw volume full: Drives putter along at 8-9MB/sec.  

Huh?  Anyone have any guesses as to why a raw volume restore would be so
much slower? 

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Drew Fabbro
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