gjournal: journaled slices vs. journaled partitions
c.kworr at gmail.com
Tue Nov 4 07:11:25 PST 2008
>>> So how do I achieve per-slice journaling instead of per-partition?
>> The docs only says this: "gjournal only supports UFS2". It does not
>> specifically say that you cannot have per-slice journaling. However,
>> since you could have other filesystems on your slice, I bet that slice
>> based journaling is not supported.
> I thought I read somewhere that because gjournal is block based and not
> really part of the filesystem, that it could easily be extended for any
> other filesystem. My imagination said that gjournal was probably
> therefore only temporarily limited to a slice full of UFS partitions.
> Anyone know for sure?
gjournal needs to know what what data is actually metadata. In case of
UFS the -J flag given to newfs tells system that using this fs we should
mark metadata for gjournal use.
>> Another tricky question: why would you journal a SWAP partition?
> Well, I don't really want to, but how big does a partition like /var
> have to be before it's no longer ill-advised to journal it individually?
> A fair bit of writing can occur in /var and the scenario my server will
> occupy has me concerned about inglorious shutdowns.
> What are the actual reasons for why journaling a small partition is
> considered a bad idea?
Journal needs to bee big enough to amass all modifications. By default
it's 1G. Just compare this to the size of your /var.
Sphinx of black quartz judge my vow.
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