Hi,
I have a progress V6.3 database (about 5.5Gig) running on a Sun sparc 10 under Solaris 2.3. I have 58 total extents in this database they are all around 100 Meg each. The DB admin prior to me have told me that the optimum size for an extent is around 100 Meg that is why they are sized this way. Now I am upgrading to an Ultra sparc 2 with 8 18 gig Ultra wide SCSI disks. and I am wondering about doing a dump and reload to reconfigure the layout of the extents.
The disks will be using the UFS filsystem which has a logical block size of ( if memory serves me right ) 8k. Now to have the optimum usage of the disks we have discussed partioning the disks using only about 10 % of each disk for the db extents thereby reducing the distance the heads would have to travel for any data on any particular disk which would hopefully give us optimum access time. Next we would layout the extents one at a time on each disk leaving one disk for a BI and one for an AI. The next question would be what size would be best for the extents.
Figuring that you would want to keep the size of the files low enough so that they don't involve triple indirect block access and that at an 8K block size the largest a file could be to use only direct blocks would be 96K and the file size for single indirect block access would be only 16M both of which are to small that means double indirect block access would be the ticket. At an 8K block size that would mean the files sizes could be as much as 32 Gig without triple indirection. The problem is there has to be a value some where with in that parameter which gives optimum performance. Also I belive there is a limit on the number of extents in V6.3 (around 100 i Think). I heard from progress that somewhere between 300 and 500 gives optimum performance. If so then I would guess that 300 would be the best since it is on the lower end of that range.
Hopefully someone else has thought this type of situation out and can tell me if I am going in the right direction and if there is anything else I should consider in sizing this.
Thanks in Advance
Michael Fields
Systems Manager
Lotus Light Enterprises
I have a progress V6.3 database (about 5.5Gig) running on a Sun sparc 10 under Solaris 2.3. I have 58 total extents in this database they are all around 100 Meg each. The DB admin prior to me have told me that the optimum size for an extent is around 100 Meg that is why they are sized this way. Now I am upgrading to an Ultra sparc 2 with 8 18 gig Ultra wide SCSI disks. and I am wondering about doing a dump and reload to reconfigure the layout of the extents.
The disks will be using the UFS filsystem which has a logical block size of ( if memory serves me right ) 8k. Now to have the optimum usage of the disks we have discussed partioning the disks using only about 10 % of each disk for the db extents thereby reducing the distance the heads would have to travel for any data on any particular disk which would hopefully give us optimum access time. Next we would layout the extents one at a time on each disk leaving one disk for a BI and one for an AI. The next question would be what size would be best for the extents.
Figuring that you would want to keep the size of the files low enough so that they don't involve triple indirect block access and that at an 8K block size the largest a file could be to use only direct blocks would be 96K and the file size for single indirect block access would be only 16M both of which are to small that means double indirect block access would be the ticket. At an 8K block size that would mean the files sizes could be as much as 32 Gig without triple indirection. The problem is there has to be a value some where with in that parameter which gives optimum performance. Also I belive there is a limit on the number of extents in V6.3 (around 100 i Think). I heard from progress that somewhere between 300 and 500 gives optimum performance. If so then I would guess that 300 would be the best since it is on the lower end of that range.
Hopefully someone else has thought this type of situation out and can tell me if I am going in the right direction and if there is anything else I should consider in sizing this.
Thanks in Advance
Michael Fields
Systems Manager
Lotus Light Enterprises