OK, this is a valid explanation. Still, i suggest you use smaller disks for your rootvg. In my experience it is best to put only filesystems really really belonging to the system (not the application, not the data, not anything else) into the rootvg. First, when you take a system backup you back up the rootvg, aka mksysb. Guess, how long that takes on a multi-terabyte rootvg and, bonus question, how big of a size the resulting mksysb-image will be. For reference, my largest database server (700G memory, ~80TB database) has a (2x, mirrored) 120GB rootvg - and this is only because the customers insisted on swap space that will never be used. Otherwise i would have gone with our 2x60GB-standard-rootvg.
Second, modern systems are usually virtual and the disks are too. There is a big difference in moving around system disks (controlled by VIOS) and non-system disks because these can be unmounted/varyoffed easily while the system is under load. Therefore it is a good idea to separate system- and non-system-disks into seaparate VGs.
First off: thank you for telling us that! I perhaps never would have had that idea at all and so i (and all the others reading this thread) learned something from here too. Absolutely commendable! A word of caution too: you shouldn't just overwrite parts of the system. AIX has a great packaging system and i suggest you use it to your advantage:
- check which package the file came from with
then replace this package with a newer version.
- if you are interested in which else files the package contains issue
to get a list of files/directories belonging to this package.
I hope this helps.
bakunin
Thanks! Yes, I agree this system should not have been installed on such large disks. There are a couple of 300GB disks in there that I think the rootvg should go on. I am new to this company and wasn't involved in installing the makesysb image. However, it is new and not in production yet, I may make the recommendation we move it to the other disks. Most of our systems do use virtual disk, however I think due to the particular function of this server they decided to install locally.
Thanks for the info about the packages, I will look into that! I have been a Unix/Linux SA for 15 years, but am very new to AIX, so I appreciate the advice.
------ Post updated at 10:06 AM ------
Just for some additional information, it looks like this problem existed on all the servers we had running AIX 7100-03-04-1441. The fileset for the dumpcheck script was bos.sysmgt.serv_aid 7.1.2.0.
Hi All,
is there any way to find out the optimal/would be size of the cor dump file generated by the system while a process got terminated abnormally?
Basically we have been asked to provide the size of the core dump file being generated by the administrators who maintained the UNIX boxes.... (4 Replies)
Friends, while taking backup on /dev/rmt/0cn it is showing device does not exists.
I have checked /dev/rmt 0cn is present there with link file created in /devices/pci@8,700000/scsi@5/st@5,0:cn
I have checked cd /devices/pci@8,700000/scsi@5 but st@5,0:cn is not there. But I found st@3,0:cn.
... (3 Replies)
1.what is dump device in AIX?...
2. i m getting this error message
The largest dump device is too small.
when i check the paging space , it is used only 41%
any help welcome (4 Replies)
Hey guys - I have made this script and for some reason, I dont see time stamp as "Month-Day-YYYY Hours-Mins" - all i see is Month and Day.
Also, my file size is approximated. For example, if the size is 19,606KB - the script shows as 20M. Is there a way to see the exact file size?
How do i... (2 Replies)
Hi,
I have a very frustrating issue! I hope you guys can assist
When a disk is presented out the iSCSI target display a lower disk capacity
SOLARIS VERSION is SOLARIS 10 05/09 Kernel Patch 139555-31
ISCSI Patch 119090-31, 141878-11
Unix Commands To discover Target
bash-3.00# i... (0 Replies)
E87EF1BE 0605150011 P O dumpcheck The largest dump device is too small.
bash-3.00$ errpt -aj E87EF1BE | more
---------------------------------------------------------------------------
LABEL: DMPCHK_TOOSMALL
IDENTIFIER: E87EF1BE
Date/Time: Sun Jun 5 15:00:01... (4 Replies)
Hi
how to change the primary dump device in a vio server ?
$ ioslevel
2.2.0.11-FP-24 SP-01
$ oem_setup_env
# sysdumpdev -l
primary /dev/sysdumpnull
secondary /dev/hd6
copy directory /var/adm/ras
forced copy flag TRUE
always allow dump TRUE
dump... (1 Reply)
Hi all
I have a query about dump device in aix, i asked this question on interview.
what is dump device, how to add dump device & its work.
kindly give this answer,
thanks in advance.
:confused: (1 Reply)
Hello Guys,
I need a little help here. I have been studying crash dump and per what I am reading, you can dedicate a slice to use as a dump device. Now when you dedicate this slice, do you have to :
1) create a mount point?
2) add entry in /etc/vfstab?
3) is this slice wu or wm?
4) should... (3 Replies)
Hi,
This is Solaris-10 box and in few of file-system (root file-system of non global zones), usage/available is not showing correct size. I am not able to figure out, what is eating up this space.
Global Server - bdrpod01
Non Global zone - bdrpod01-zputq01
root@bdrpod01:/root# df -h... (2 Replies)
Discussion started by: solaris_1977
2 Replies
LEARN ABOUT FREEBSD
dumpon
DUMPON(8) BSD System Manager's Manual DUMPON(8)NAME
dumpon -- specify a device for crash dumps
SYNOPSIS
dumpon [-v] special_file
dumpon [-v] off
dumpon [-v] -l
DESCRIPTION
The dumpon utility is used to specify a device where the kernel can save a crash dump in the case of a panic.
Calls to dumpon normally occur from the system multi-user initialization file /etc/rc, controlled by the ``dumpdev'' variable in the boot
time configuration file /etc/rc.conf.
The default type of kernel crash dump is the mini crash dump. Mini crash dumps hold only memory pages in use by the kernel. Alternatively,
full memory dumps can be enabled by setting the debug.minidump sysctl(8) variable to 0.
For systems using full memory dumps, the size of the specified dump device must be at least the size of physical memory. Even though an
additional 64 kB header is added to the dump, the BIOS for a platform typically holds back some memory, so it is not usually necessary to
size the dump device larger than the actual amount of RAM available in the machine. Also, when using full memory dumps, the dumpon utility
will refuse to enable a dump device which is smaller than the total amount of physical memory as reported by the hw.physmem sysctl(8) vari-
able.
The -l flag causes dumpon to print the current dump device or _PATH_DEVNULL ("/dev/null") if no device is configured.
The -v flag causes dumpon to be verbose about its activity.
IMPLEMENTATION NOTES
Since a panic(9) condition may occur in a situation where the kernel cannot trust its internal representation of the state of any given file
system, one of the system swap devices, and not a device containing a file system, should be used as the dump device.
The dumpon utility operates by opening special_file and making a DIOCSKERNELDUMP ioctl(2) request on it to save kernel crash dumps. If
special_file is the text string: ``off'', dumpon performs a DIOCSKERNELDUMP ioctl(2) on /dev/null and thus instructs the kernel not to save
crash dumps.
Since dumpon cannot be used during kernel initialization, the dumpdev variable of loader(8) must be used to enable dumps for system panics
which occur during kernel initialization.
FILES
/dev/{ada,da}?s?b standard swap areas
/etc/rc.conf boot-time system configuration
SEE ALSO fstab(5), rc.conf(5), config(8), init(8), loader(8), rc(8), savecore(8), swapon(8), panic(9)HISTORY
The dumpon utility appeared in FreeBSD 2.1.
BUGS
Because the file system layer is already dead by the time a crash dump is taken, it is not possible to send crash dumps directly to a file.
BSD October 8, 2014 BSD