PSTAT - Swap info

[Przemyslaw Fafara]

Hello

I'm writing simple monitoring tool using pstat interface. How to obtain information how much swap space on disk dev is used? When I'm using pstat_getvminfo I get sum of reserved swap on device and used space:

total_sw_dev = vbuf.psv_swapspc_max;
avail_sw_dev = vbuf.psv_swapspc_cnt;

I've looked through forum and I can't find the answer.

[Steven E. Protter]

Shalom,

I usually use vmstat or swapinfo -tam

You can parse the output any way you want to get data back into your program.

SEP

[Don Morris_1 · Accepted solution]

You have to use pstat_getswap() to interate through the swap devices/FS's for that information.

[Court Campbell]

http://www.docs.hp.com/en/1216/pstat_whitepaper.pdf

[Przemyslaw Fafara]

I've checked pstat_getswap() but I can't find where this function return's used blocks on swap device.

struct __pss_blk {
struct __psdev Pss_dev; /* Device specification */
_T_ULONG_T Pss_start; /* For 300,700: starting blk */
_T_ULONG_T Pss_nblks; /* OBSOLETE, was total # of blocks */
_T_ULONG_T Pss_nblksavail; /* # of blocks available */
};

This struct returns info only about available blocks, not used blocks.

[Don Morris_1]

Look lower in vm_pstat_body.h --

#define pss_nblksenabled pss_un.Pss_blk.Pss_nblks

That's what you want, total blocks enabled on the device (for the Device case). pss_nfpgs is then pages free, pss_nblksavail is available blocks [this is usually when maxswapchunks or swchunk is too small and the system has to consider some of the possible blocks as unusable].

[Sandman!]

Look at the declaration of struct __pst_swapinfo in the vm_pstat_body.h file.