Re: Database Usage of Unix FFS

Lee E Parsons (lparsons_at_world.std.com) wrote:
: Situation: Large database files are the only files on a group of UNIX
: Fast FileSystem partitions. These files are created by the
: database on initialization and if any are deleted all
: are deleted. The files would likely be 50 to 100mb each.
: 1 partition = 1 drive.
:
: Given the low number of unix creates/delete on these drives, please
: comment on the following statements.
:
: 1) It would seem reasonable in this case to turn the minfree option
: on the FFS down as low as possable (0%) and use as much of the
: drive as you can (100%).
:
: (I/O distribution considerations aside. Of course.)
:
: Since you wont be doing any creates or deleted you don't need any
: free space to increase your performance.
:
: 2) Since no deletes are happening you don't have to worry about holes
: in the data. ie) you won't have 100 meg in the middle of the drive
: you need to use.
:
: Even if you needed to add an additional datafile it would just get
: slapped on the end of the last datafile in one contiguous space.
:
: --
: Regards,
 

: Lee E. Parsons
: Systems Oracle DBA lparsons_at_world.std.com

    One would also want to increase the bytes/inode (the default value of 2048 bytes/inode on Solaris 2.3, for example, uses up 62MB of a 1GB disk). I also increased the number of cylinders/group, in order to get larger bands, and to reduce what I thought was an excessive number of superblock copies (> 100) on a 1GB disk. Received on Wed Feb 23 1994 - 11:57:15 CET