adding 4 gb memory today..

[rmueller58]

Our FE is coming out to install 4gb of Memory.

is there any "kernel" concerns I should consider before bringing the system back on line?

Do I need to make any modifications to "swap"?
# swapinfo
Kb Kb Kb PCT START/ Kb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 3284992 0 3284992 0% 0 - 1 /dev/vg00/lvol2
reserve - 2081464 -2081464
memory 2335744 1831960 503784 78%


# more /usr/sam/lib/kc/tuned/kern_07072005.tun
ESU#3 7-7-05 Kernel Parameters
* Tunable parameters
NSTRBLKSCHED 2
NSTREVENT 50
NSTRPUSH 16
NSTRSCHED 0
STRCTLSZ 1024
STRMSGSZ 65535
acctresume 4
acctsuspend 2
aio_listio_max 256
aio_max_ops 2048
aio_physmem_pct 10
aio_prio_delta_max 20
allocate_fs_swapmap 0
alwaysdump 0
bootspinlocks 256
bufcache_hash_locks 128
bufpages (NBUF*2)
chanq_hash_locks 256
create_fastlinks 0
dbc_max_pct 20
dbc_min_pct 7
default_disk_ir 0
desfree 0
disksort_seconds 0
dnlc_hash_locks 64
dontdump 0
dskless_node 0
dst 1
eisa_io_estimate 0x300
eqmemsize 15
fcp_large_config 0
file_pad 10
fs_async 0
ftable_hash_locks 64
hdlpreg_hash_locks 128
hfs_max_ra_blocks 8
hfs_ra_per_disk 64
hpux_aes_override 0
initmodmax 50
io_ports_hash_locks 64
iomemsize 40000
km_disable 0
ksi_alloc_max (NPROC*8)
ksi_send_max 32
lotsfree 0
max_async_ports 50
max_fcp_reqs 512
max_mem_window 0
max_thread_proc 256
maxdsiz 536870912
maxdsiz_64bit 0x0000000040000000
maxfiles 1024
maxfiles_lim 1024
maxqueuetime 0
maxssiz 0x00800000
maxssiz_64bit 0x00800000
maxswapchunks 16384
maxtsiz 134217728
maxtsiz_64bit 0x0000000040000000
maxuprc (NPROC*9/10)
maxusers 512
maxvgs 10
mesg 1
minfree 0
modstrmax 500
msgmap (2+MSGTQL)
msgmax 8192
msgmnb 16384
msgmni (NPROC)
msgseg 32767
msgssz 8
msgtql (NPROC)
nbuf 0
ncallout 2064
ncdnode 150
nclist (100+16*MAXUSERS)
ncsize (NINODE+VX_NCSIZE)
ndilbuffers 30
netisr_priority -1
netmemmax 0
nfile (15*NPROC+2048)
nflocks 4096
nhtbl_scale 0
ninode 2048
nkthread 2048
nni 2
no_lvm_disks 0
nproc (((10*MAXUSERS)/3)+128)
npty 512
nstrpty 512
nstrtel 512
nswapdev 10
nswapfs 10
nsysmap ((NPROC)>800?2*(NPROC):800)
nsysmap64 ((NPROC)>800?2*(NPROC):800)
num_tachyon_adapters 0
o_sync_is_o_dsync 0
page_text_to_local 0
pfdat_hash_locks 128
public_shlibs 1
region_hash_locks 128
remote_nfs_swap 0
rtsched_numpri 32
scroll_lines 100
scsi_max_qdepth 8
scsi_maxphys 1048576
sema 1
semaem 16384
semmap (SEMMNI+2)
semmni 4096
semmns 4096
semmnu 30
semmsl_override 2048
semume 10
semvmx 32767
sendfile_max 0
shmem 1
shmmax 2048000000
shmmni 512
shmseg 256
st_ats_enabled 0
st_fail_overruns 0
st_large_recs 0
st_san_safe 0
streampipes 0
swapmem_on 1
swchunk 2048
sysv_hash_locks 128
tcphashsz 0
timeslice (100/10)
timezone 420
unlockable_mem 0
vnode_cd_hash_locks 128
vnode_hash_locks 128
vps_ceiling 16
vps_chatr_ceiling 65536
vps_pagesize 4
vx_maxlink 32767
vx_ncsize 1024
vx_ninode 0
vx_noifree 0
vx_nothrottle 1
vxfs_max_ra_kbytes 1024
vxfs_ra_per_disk 1024

[Pete Randall · Accepted solution]

You might want to look at swchunk in case you need to increase your swap area to better match you new increased memory.


Pete

[DCE]

You have psuedo swap activated (swapmem_on=1), so there is nothing you need to do. You can, if you wish, add more phsical swap, but I do not believe it will be neccessary

[rmueller58]

Thanks guys for the quick reply.

I just wasn't sure whether the "swapmem_on" kernel parameter would handle it as dynamic.

[Borislav Perkov]

Hi,
You have to make modification of swap space. Depending of the applications running on the server swap should be at least big as your physical memory, the recomendation is 1.5 to 2 time physical memory. But because of the continuity of swap space on disk you need to change it size making boot from the IgniteUX recovery tape. You can find the procedure describet in IgniteUX documentation or in mauals on the system(man make_tape_recovery). The kernel parameters depend also of the application running on the server, you should consult the documentation or the support for that application, specialy databases.

Regards,
Borislav

[Bill Hassell]

I'll disagree with the 1.5x to 2x swap recommendation. This is an archaic recommendation leftover from the days when memory for HP-UX was 128 to 512 megs. As you can see from your swapinfo command, you're using 0% which means the disk space is wasted. The only time massive swap is needed is when certain applications like Oracle or SAP are first installed. For whatever reason, they seem to require outrageous amounts of RAM (6-25 Gb) and since most users don't have this much, you add thiws extra RAM using swapon to provide a temporary swap area.

Once installed, reboot the systrem and the temp swap goes away. I would also reduce the dbc_max_pct value from 20 to 10 or 12 so your buffer cache is maxed at about 400-600 megs.

[rmueller58]

Thanks all,

Bill, I will change the max_dbc_pct to recommended.

We are running Informix 7.3.1 but it is already installed and running. I here the 1.5 times figured bantered around, and if need be I can muck with it, but I gather I shouldn't have to.. As it shouldn't require it..

[rmueller58]

Thanks All.

Questions answered..