11-13-2008
Quote:
Originally Posted by
MikaBaghinen
My understanding is, that a system should panic whenever cached data cannot be written to a disk device.
Absolutely not. A system should panic when it is so confused that attempting to write cached data may cause further damage. Imagine a system with external disks and you bump your knee into a power button, turning off the disk. All you need to do is power the drive back on. And yes, that really happened to me and I was grateful that the HP-UX system did not panic.
9 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
Hi all,
I am writing a script to monitor some processes existence in the system. It works perfectly by running the script manually in commend line. However, when I put it under cron to run it failed. Everything time when the variable is null in the if statment. it failed and quitted. Here is... (2 Replies)
Discussion started by: stancwong
2 Replies
2. UNIX for Dummies Questions & Answers
Hello,
I am learning to debug in sgi-Irix6.5, after a core dump, I was adviced to perform a "strace", but I got the following information:
ERROR: tracer already exists
what shall I do now?
Thanks a lot
Daniel (0 Replies)
Discussion started by: lakeat
0 Replies
3. SCO
I am a 10 years windows person with basic unix training (very basic).
I have a sco server where it originally had 3 physical drives. Drive 0 had to be replaced so I did that but because I am really new to Unix I was afraid to detroy the data on DRIVE 1 and 2, so I took them out when I loaded the... (3 Replies)
Discussion started by: mhenry
3 Replies
4. UNIX for Advanced & Expert Users
Greetings Forumers!
I ran into an issue after running luupgrade on v880 running Solaris 8. I want to upgrade to Solaris 10.
When I rebooted the system I noticed the file systems listed as such:
# df -h
Filesystem size used avail capacity Mounted on
/dev/dsk/c1t1d0s0 ... (2 Replies)
Discussion started by: bluescreen
2 Replies
5. AIX
Hi guys,
I am newbie to AIX. We are planning to attach external HDS array to AIX servers where VCS in installed. Anyone know step by step procedure for attaching and detaching HDS array?. If yes, please post reply for the same.
Thanks in advance guys. (5 Replies)
Discussion started by: prtaix
5 Replies
6. Solaris
Do I need to reinstall/rerun JASS after upgrading from Sol9 to Sol10?
Just wondered if the upgrade procedure overwrote any of the settings etc? (0 Replies)
Discussion started by: psychocandy
0 Replies
7. UNIX for Advanced & Expert Users
We have two node cluster with OS disk mirrored under SVM. There is slight disk problem on one of the mirror disk causing cluster to panic.
Failure of one mirror disk causing VCS to panic the node. Why VCS is not able to write /var filesystem, as one of the disk is healthy.
... (1 Reply)
Discussion started by: amlanroy
1 Replies
8. Post Here to Contact Site Administrators and Moderators
An 'addition' to the "Homework & Classes" requirements..
As i am someone without paper, i just figured i got tempred reading such a question.
To avoid such 'feelings' in future, i'd be thankfull if the 'kind & definition of the course' would be required too.
As in (i dont know about proper... (2 Replies)
Discussion started by: sea
2 Replies
9. Shell Programming and Scripting
Hello,
Here is my crontab
# Reboot one Sunday out of 2 at 02:00
0 2 * * 0/2 /usr/bin/reboot
2017-04-16
2017-04-23
2017-04-30
and so on
I tested my crontab here, it seems to work
Http://cron.schlitt.info/index.php?c...=100&test=Test
However on my distrib linux mageďa
When I register... (4 Replies)
Discussion started by: amazigh42
4 Replies
LEARN ABOUT HPUX
default_disk_ir
default_disk_ir(5) File Formats Manual default_disk_ir(5)
NAME
default_disk_ir - enable and disable use of device's write cache in the SCSI subsystem (OBSOLETE)
VALUES
Failsafe
Default
Allowed values
Recommended values
DESCRIPTION
Note: This tunable is obsolete. HP no longer allows enabling, by default, write cache for all direct access devices on the system. It is
still possible to enable write cache for a specific device through the command. See scsictl(1M).
This tunable enables(1) or disables(0) the Immediate Reporting behavior of the SCSI subsystem, also known as Write Cache Enable (WCE).
With Immediate Reporting enabled, disk drives that have data caches return from a system call, including raw writes, when the data is
cached, rather than returning after the data is written to the media. This sometimes improves write performance especially for sequential
transfers.
Cached data can be lost if a device power failure or reset occurs before the device writes the cached data to media. Because of these
risks, the recommended value for this parameter on servers is Immediate Reporting disabled(0).
Although not an option to the mount command, this tunable has a profound effect upon filesystem and raw disk performance and, conversely,
data integrity when system resets occur. This tunable also affects delayed-write versus write-through-filesystem behavior.
Who Is Expected to Change This Tunable?
Anyone.
Restrictions on Changing
Changes to this tunable will take effect when the device is first opened.
When Should the Tunable Be Turned On?
When a third party application vendor recommends it. For normal use, HP strongly recommends you don't enable this tunable.
What Are the Side Effects of Turning the Tunable On?
Since enabling this tunable circumvents the protections provided by LVM or RAID, there is a strong risk of filesystem corruption and data
loss in case of a device power failure or reset.
When Should the Tunable Be Turned Off?
HP recommends you always disable this tunable. This is especially true if you don't want to take the risk of filesystem corruption and
data loss in case of a device power failure or reset.
What Are the Side Effects of Turning the Tunable Off?
This might reduce the performance of disk write (not read) access while eliminating the risk of filesystem corruption and data loss in case
of a device power failure or reset.
What Other Tunables Should Be Changed at the Same Time?
None.
WARNINGS
All HP-UX kernel tunable parameters are release specific. This parameter has been obsoleted for HP-UX 11i Version 3.
Installation of optional kernel software, from HP or other vendors, may cause changes to tunable parameter values. After installation,
some tunable parameters may no longer be at the default or recommended values. For information about the effects of installation on tun-
able values, consult the documentation for the kernel software being installed. For information about optional kernel software that was
factory installed on your system, see at
AUTHOR
was developed by HP.
SEE ALSO
write(2), scsi(7).
OBSOLETE
Kernel Tunable Parameter default_disk_ir(5)