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chdev
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Updating AIX Virtual SCSI adapter attributes without an outage
Need to update the running attributes of a virtual SCSI adapter on
an AIX system? Try these steps. I want to change value for the vscsi_err_recov attribute
to fast_fail .
I can’t do this if the adapter is busy i.e. has open/available paths to a disk device. #
lsattr -El vscsi2 vscsi_err_recov
delayed_fail
N/A
True vscsi_path_to
0 Virtual
SCSI Path Timeout True #
chdev -l vscsi2 -a vscsi_err_recov=fast_fail Method
error (/usr/lib/methods/chggen):
0514-029 Cannot perform the requested... [More]
Tags:  vscsi gibson cfgmgr chdev aix chris rmpath lspath |
Checking your queue depth with kdb.
Just say you
change the queue_depth on a hdisk
with chdev –P . This updates the devices
ODM information only, not its running configuration. The new value will take
effect next time I reboot the system. So now I have a different queue_depth in the ODM compared to the
devices current running config (in the kernel). What if I
forget that I’ve made this change to the ODM and forget to reboot the system
for many months? Someone complains of an I/O performance issue....I check the
queue_depths and find they appear to be set appropriately... [More]
Tags:  lsattr chris 7.1 chdev queue_depth odm aix -p kdb gibson 6.1 |
Can't change max_transfer for a VSCSI hdisk? Check your vtopt devices!
When attempting to change the max_transfer attribute on a VSCSI hdisk, the following error was displayed: #
chdev -l hdisk0 -a max_transfer= 0x100000 -P Method
error (/etc/methods/chgdisk):
0514-018 The values specified for the following attributes
are not valid: max_transfer
Maximum TRANSFER Size The
desired value, 0x100000, was an allowed value for this type of device (as shown
in the lsattr output below): #
lsattr -El hdisk0 PCM
PCM/friend/vscsi
Path Control... [More]
Tags:  rmdev vtopt0 max_transfer rmvdev aix vios chdev hdisk cd0 virtual_optical vio |
VLAN tagging and the VIOS: some questions and answers.
Here are some questions I received recently regarding VLAN
tagging on the VIO server. My answers are shown in green . “Hi Chris, Q: I’m trying to
understand when, where and why there would be the need to use ‘mkvdev –vlan
(etc.) on the VIOS, and I’m wondering whether you would be able to clarify this
for me, please. Is it necessary to add
the VLAN tag devices to the SEA, or is it suffice to just have them defined
within the Virtual Ethernet itself which is part of the SEA?” A:
It is suffice to simply define the VLAN ids assigned... [More]
Tags:  tagging ent6 sea virt_adapters=ent3 vlan power7 hmc tag -attr mkvdev ent5 -dev -vlan chdev dynamic dlpar |
Checking num_cmd_elems for VFC adapters with kdb
This entry is
similar in theme to one of my previous posts about verifying your hdisk queue_depth settings with kdb . This time we want to check if an attribute for a Virtual FC (VFC)
adapter has been modified and whether or not AIX has been restarted since the
change. The attribute I’m interested in is num_cmd_elems .
This value is often changed from its default settings, in AIX environments, to improve
I/O performance on SAN attached storage. From
kdb you can identify the VFC
adapters configured on an AIX system using the vfcs... [More]
Tags:  -p odm kdb lsattr chris_gibson num_cmd_elems adapter vfcs aix chdev reboot vfc |
Tuning Virtual Ethernet adapters for (even) better backup performance.
Are you backing up your AIX systems
over Virtual Ethernet adapters? Of course you are, who isn’t right? Are your
backup server and clients on the same physical POWER system? You are most
likely backing up over Virtual Ethernet to another AIX LPAR that is running
your enterprise backup software, such as TSM or Legato Networker for example.
And you probably have a dedicated private virtual network (and adapters) on
both the clients and the server to handle the traffic for the nightly backups.
The next question is, have you tuned your... [More]
Tags:  min_buf_huge=96 backup netstat slow hypervisor -a aix max_buf_huge=128 tsm chris_gibson min_buf_large=96 max_buf_large=256 networker min_buf_medium=512 -l adapter max_buf_medium=1024 virtual ent1 chdev –a ethernet |