9.1 Snapshot 06-05-2012 No ZIL ing root pool ZFS
I'll have to ask around about not being able to have a speratem ZIL when
using a ZFS on root system. A quick google search isn't turning anything
up about that. According to the manpage portion about ZIL, it doesn't
mention this anywhere, and seems to indicate that you can add / remove
log devices at will:
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The ZFS Intent Log (ZIL) satisfies POSIX requirements for synchronous
transactions. For instance, databases often require their
be on stable storage devices when returning from a system call.
other applications can also use fsync(2) to ensure data stability. By
default, the intent log is allocated from blocks within the main pool.
However, it might be possible to get better performance using separate
intent log devices such as NVRAM or a dedicated disk. For example:
# zpool create pool da0 da1 log da2
Multiple log devices can also be specified, and they can be
the EXAMPLES section for an example of mirroring multiple log devices.
Log devices can be added, replaced, attached, detached, imported and
exported as part of the larger pool. Mirrored log devices can be
by specifying the top-level mirror for the log.
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