AW: Re: File system performance and pg_xlog (More info) - Mailing list pgsql-hackers

From Zeugswetter Andreas SB
Subject AW: Re: File system performance and pg_xlog (More info)
Date
Msg-id 11C1E6749A55D411A9670001FA6879633682B7@sdexcsrv1.f000.d0188.sd.spardat.at
Whole thread Raw
List pgsql-hackers
> > >From a portability standpoint, I think if we go anywhere, it would be to
> > write directly into device files representing sections of a disk.
> 
> That makes sense to me.  On "traditional" Unices, we could use the raw 
> character device for a partition (eg /dev/rdsk/* on Solaris),

On Solaris this is (imho) the exact wrong way to do it. On Solaris you would 
typically use logical volumes created with Veritas LVM.
Imho the times where you think of a raw device beeing one physical disk partition 
are fortunately over, since LVM's are widespread enough.

> and on Linux we'd use /dev/raw*, which is a mapping to a specific partition
> established before PG startup.

Usually you would use a symlink to such a raw device if such a device needs to be 
in /dev.

> I guess there would need to be a system table that keeps track of 
> (dev, offset, size) tuples for each WAL file.

This would need to be hidden in a new smgr layer.

Andreas


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