Thanks for the replies from: sunsa_tx@yahoo.com David Booth Tim Chipman Chris Dantos Victor Karpovich Wesley W. Garland Stan Pietkiewicz Darren Dunham Special thanks to: Kevin L. Prigge Colby Johnston hike1272-sunhelp@yahoo.com Kevin Buterbaugh ---------------------------------------------------------- Kevin L. Prigge Sent me these links for Solaris 9 and Solaris 8 respectively and I summed it up below for Solaris 8:(Also keep in mind a large enough space for crash dumps) For Solaris 9: http://docs.sun.com/db/doc/817-2874/6migoiaao?a=view Solaris 8: http://docs.sun.com/db/doc/817-1658/6mhcgsu9m?a=view System Type Swap Space Size Dedicated Dump Device Size Workstation 4 Gbytes of physical memory 1 Gbyte 1 Gbyte Mid-range server 8 Gbytes of physical memory 2 Gbytes 2 Gbytes High-end server 16 to 128 Gbytes of physical memory 4 Gbytes 4 Gbytes ---------------------------------------------------------------------------- ---------------------------------------------------------------------------- --------------- Colby Johnston summed it up with following and a nice link: I would not allocate more that 4Gb of swap unless your applications have special swap requirements. The way sun virtualizes memory now, there is usually no need for the old 1 to 1 ratio of physical memory to swap space. Swap is now defined as disk backed physical memory plus a portion of real memory. With this in mind, even though you may allocate a 4Gb swap partition, your "swap -s" output may show you are potentially using more than that. The "swap space" used on the system is dynamic and may not always equal the space defined in the swap partition. See the following document on for a better explanation on planning the swap space on Solaris. There is a section called "Planning for Swap space" which should give you a good idea of how to initially configure swap. http://docs.sun.com/db/doc/817-2874/6migoiaaj?q=swap&a=view ---------------------------------------------------------------------------- -------------------------------------- hike1272-sunhelp@yahoo.com says: sun has changed its swap recommendations with the advent of large amount of real memory. under normal situations, you will never use all 16gbs of rams for processes. instead of swapping, your system will page (to unused portions of real memory). at this point, the major concern are core dumps. ideally you want enough swap for an entire core dump. we have 12gb of ram and setup a 12gb swap partition. since our internal disk are for os only and hold no data, this is not an issue. what sun recommended in the sysadm classes is to create a smaller swap partition. if more space is needed, a swap file can be created. also, sun now recommends only "/" and swap partitions. following this recommendation, a large amount of the "/" partition will be unused; there will be plenty of room for a swap file. ---------------------------------------------------------------------------- ------------ Kevin Buterbaugh has this to add: You're right, the old rules about swap no longer apply. As long as you have sufficient physical memory for your peak workload, you can actually run with no swap whatsoever configured. However, that's generally not recommended, mainly because in the (rare) event of a system panic, it will want to dump to the swap space. How much swap you should configure really depends on the application you're going to run on the server and its' requirements. We generally configure swap = RAM on our smaller ( < 16 GB RAM) boxes. For larger boxes, it's more like swap = RAM / 2. YMMV... ---------------------------------------------------------------------------- ----------------------------------------- thanks for all of the replies and here is my original POST: Kirk Gilliam ---------------------------------------------------------------------------- ---------------------------------------- Hello -- I have searched the archives and I still have not found an answer. I have three V440's with four 1.28GHZ processors and 16 GB of RAM and four 32 GB disks. The old Sun way for configuring the swap partition was to configure the partition for one to two times the physical memory. Since memory and disk are getting cheaper, what is the new rule of thumb? Should I give the swap partition a 1 to 1 relation which would be a 16 GB swap partition? That sure seems like a lot of wasted space. What problems would I run into if I made the swap partition 8 GB or 4 GB. What if I had one 36 GB disk and 32 GB of RAM, you would not make swap 32 GB, would you? Thanks, I will summarize, Kirk Gilliam _______________________________________________ sunmanagers mailing list sunmanagers@sunmanagers.org http://www.sunmanagers.org/mailman/listinfo/sunmanagersReceived on Thu Jan 22 12:48:41 2004
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