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  http://publib.boulder.ibm.com/infocenter/systems/index.jsp?topic=/com.ibm.aix.cmds/doc/aixcmds6/vmo.htmWhat is mean by mount the CD ROM?************************************************************************ * How will increase the File systems? smit lv, set charateristics, change- insure that the maximum number of logical partitionstimes the size of the physical partitions exceeds the size that you want to change the filesystem size to.lsvg vgname will give you the size of the physical partition. Then - smitty jfs - change/show - the numnber of units is in 512 byte blocks - so this number should beyour final size of the file system in bytes divided by 512.you will need to do some calculations (free PPs, size of a PP, etc) to calculate the sizeyou need. ??? not a lot of math though: before 5.2, you want to add 1GB to a file systemtake 512 (block size)512 times 2 ==> 2blocks 1K 512 times 2048 ==> 2048blocks is 1M512 times 2048x1024 ==> 20971525blocks is 1GBin chfs command specifychfs -a size=+20971525 /file/system/nameor specify +20971525 in SMIT panel to add 1GBfrom 5.2 onwardschfs -asize=+1G /file/system/nameor use appropriate SMIT fields (value=1 unitsize=gigabytes)It still stands that the underlying LV needs to be accomodating (max number of PPs) butchfs will tell you if this isn't so. You may need to do some more math to get that limithigh enough or simply start by doubling the current value (smit chlv)  ************************************************************************ *How will you create the file systems? $ mkfs: destroy /dev/hdisk1 (y)? ylogform: Format inline log for <y>?yFile system created successfully.142077508 kilobytes total disk space.Device /dev/hdisk1:Standard empty file systemSize: 284155016 512-byte (DEVBLKSIZE) blocks$ mount /dev/hdisk1 /data Disk driver configuration Utility smit disk Add a Volumegroup smit vgCreate new filesystems smit fsCreate a mount point mkdir /disk1Mount filesystems mount /dev/hd0/? /disk1Show mounted Filesystems lsfsBackup Volumegroups smit vgbackupInstall packages smitty install_latestUpgrade a package installp -aCreate an installation server for network installation nimconfigSet up a client for network installation nim -o bos_inst *Which command will use list the paging space? VMO ( Virtual Memory Manager) Data is essentially held in pages of 4096b, and a page in RAM is accessible by theCPU, if the page is on disk the CPU can't access it directly.A page fault occurs when a wanted page address does not translate to a real memoryaddress. At this point the Virtual Memory Manager (VMM)knows it needs to get datafrom disk and place it in RAM - it therefore checks to see that there is space in RAM inwhich to out this data.  If there's enough room, VMM checks to see if the wanted page has been usedpreviously by this process:- if not, an initial page fault , VMM allocates _two_ pages for the data; one in RAMand the other on a backing page on disk where it can go if it has to be temporarilyremoved from RAM. This is known as late page space allocation .- if it has, a repage fault I/O is scheduled to bring the data back from disk and intoRAM - the act of resolving this repage fault is called a page-in (the process that iswaiting for this to happen is in a page wait state ).So what happens if there's not enough room in RAM to put the page? Well the pagestealer is there to ensure that there is a supply of free RAM pages available for aninitial page fault. If the number of free RAM pages drops below a specified value thenthe page stealer will try and get some pages back. It keeps on stealing pages until itreaches an upper limit.So how does it decide which pages to steal? The page stealer will select the leastrecently used, or LRU, pages. If the page has been modified in RAM it's classed as adirty page and is put to a backing store (either page space or a filesystem); if it'sclean (the copy in RAM matches the copy in page space) then the RAM page ispurged.Note that the page space is used for non-persistent or working pages, and thefilesystem is used for persistent or file pages. There is, of course, a basic assumption here that all stale pages are treated equally,i.e. whether it's a file- or nonfile- page makes no difference to the page stealer.However this is not the case. Increased paging activity makes VMM act upon thedifferent types of (stale) pages in a different manner. When the number of [stale] filepages exceed a number - set by the maxperm threshold - the page stealer will stealonly file pages.If the number of stale file pages is below maxperm (but above the set minpermthreshold) then two other considerations come into play. The VMM checks the repage rates of both file and nonfile pages, and will steal filepages if the file page repage rate is higher than the repage rate for nonfiles.If this not the case then both types of pages are treated as equal victims.PERFORMANCE HITS / ACTUAL DISK I/O... To understand the performance hit of the paging figures that you come across, youneed to realise that page faults do NOT (necessarily) result in diskactivity. Remember from above that only the repage fault - the act of bringing backpreviously used data into memory - causes disk I/O to be scheduled.Page out I/O only occurs when a page is stolen by the page stealer AND is marked as'dirty'. This only happens when there is a shortage of free RAM pages. Hence thepage-out figure can be an indicator of how memory constrained the system is. Thevmstat command is only of limited use as it just reports activity concerned with pagespace (and not paging to/from filesystem space).  If the system consistently appears to hover around the minperm value (the fre column in vmstat) then it does not follow that the system is memory constrained -consider the scenario where an initial page fault is resolved by purging a clean, butstale, page. In this there is paging activity but no corresponding I/O.System performance may be improved by reducing the amount of RAM that filepages occupy - this ensures that working pages are not continually being pushed outto make way for file pages. This can be achieved through the use of the vmtune command (/usr/samples/kernel)and DECREASING values for minperm and maxperm.PAGING SPACESo how much page space do I need? For systems that have up to 256MB of realmemory, use the well known formula...page_space = 2 x real_memory...for those systems with more than 256MB of real memory use...page_space = 512MB + (real_memory - 256MB) * 1.25 The following should also be adhered to where possible:1. configure just one paging space per disk2. use between 2 and 6 paging spaces in a medium size system3. configure the paging spaces on each disk to be the same size ************************************************************************How will increase the paging space? Hi all - I'm having some memory issues where I'm running out of paging space. I'm not sure if I need to add more ram tothe server. Or if I can get by, by increasing the paging space. I'm hoping I can increase the paging space. I know I cando this using SMIT. But I'm not sure if I need to add allocate some space to a logical volume group first. I have a lot of unallocated free space that can be added if need be. Or if I can simply plug in a number using smitty mkps. I have a 1 gbram module in the system, but it looks like the system only recognizes 900 mb based on the number the bootinfo -r command returns. And it looks like I've got 1.5 gb of paging space. I have a pair of 72 gb drives that are mirrored.Based on the output of the commands I've ran below, what can I safely increase my paging space to, and what number do I need to plug in via smitty mkps?Or do I need to add ram the system and then increase the paging space?Thanks# lsvg -l rootvgrootvg:LV NAME TYPE LPs PPs PVs LV STATE MOUNT POINThd5 boot 1 2 2 closed/syncd N/A
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