Mary, If you have sufficient paging space, you might consider using V-disk instead of T-disk. As Nick pointed out, they are not subject to fragmentation and the limits for the individual users and the system as a whole can be set and adjusted dynamically. If you are not already paging constrained and you have the space, it might be a way out of the fragmentation problem. Look under HELP CP DEFINE (RELATED and select VDISK. You may also need to set limits using SET VDISK.
We have been using V-disk in place of T-disk for the past several years and have never had a problem with it. -----Original Message----- From: VM/ESA and z/VM Discussions [mailto:[EMAIL PROTECTED] On Behalf Of Mary Zervos Sent: Tuesday, January 24, 2006 6:43 AM To: [email protected] Subject: Re: Tdisk question Thanks Jim for the insight. I had forgotten about fragmentation. Mary Jim Bohnsack wrote: > Mary--What you're seeing is fragmentation. TDISK is allocated in one > whole piece to a user. Think of PC disk allocation that you see when > you run a defrag. If you have 1 allocated cylinder out in the middle > of an otherwise empty 100 cylinder TDISK space, you cannot allocate a > 99 cyl TDISK. You would get that by the first user getting 50 > cylinders and the 2nd user getting 1 cylinder. When the first user > detaches the 50 cyl. disk, the 2nd user still has the 1 cyl in the > middle. You are left with 99 cylnders in total free but you can only > allocate a max of 50 cylinders and 49 cylinders. > > Jim > > At 09:17 AM 1/24/2006, you wrote: > >> I have 500 cyl. of tdisk defined on one pack and 50 cyl. of tdisk >> defined on another. One user used the 50 cyl. on the second pack >> and about 24 users have used 215 cyl.(43%used) on the first pack. >> Why is it that I can only allocate a 130 cyl. maximum tdisk on the >> first pack but can then go ahead and allocate a 110 cyl. tdisk, >> instead of being able to allocate *one* 240 cyl. tdisk? >> >> Thanks for any help. >> >> Mary Zervos >> VM Systems Programmer >> Binghamton University >> [EMAIL PROTECTED] > > > Jim Bohnsack > Cornell Univ. > (607) 255-1760
