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Full Discussion: MPIO reliability
Operating Systems AIX MPIO reliability Post 302491948 by kah00na on Friday 28th of January 2011 05:30:04 PM
Old 01-28-2011
UPDATE: Sorry: The hcheck_interval idea was already mentioned by smurphy. I should have moved on to page 2.

One other thing to check is your "hcheck_interval" which is set at the disk level. The hcheck_interval tells your system how often to check, or re-check, FAILED paths and inactive ENABLED paths (in the case of "algorithm" being set to "fail_over") to ensure they are still connected and functioning. I suggest setting your hcheck_interval to 3600 (once an hour). You'll have to set this on all your disks individually. If the hcheck_interval is set to "0", then this disables it and the disk will never automatically change out of a FAILED or MISSING state.

Remember that MPIO is not like etherchannels, where it automatically re-enables all the paths as soon as the plug is back in. Something has to occur on the disk side to make it recheck them. Either the hcheck_interval comes around again, or you unplug your secondary fiber car which will cause AIX to suddenly start sending checks for all your disks down all the paths, FAILED or MISSING, and try to find a path that is working and it will set it back to ENABLED if it finds one.

Code:
hostname:/:$ lsattr -El hdisk0 | egrep "hcheck_interval"
hcheck_interval 3600                             Health Check Interval      True
hostname:/:$

Also, you can re-enable the paths manually by doing a chdev on it:
Code:
chdev -l hdisk0 -p vscsi0 -s enable

You can also see which path is being used by watching for numbers increasing in the output of "iostat -m":
Code:
hostname:/:$ iostat -m hdisk0

System configuration: lcpu=4 drives=7 ent=0.20 paths=10 vdisks=2

tty:      tin         tout    avg-cpu: % user % sys % idle % iowait physc % entc
          0.0         10.6                0.9   0.5   98.3      0.3   0.0    1.6

Disks:        % tm_act     Kbps      tps    Kb_read   Kb_wrtn
hdisk0           0.3      46.3       3.7   180755051  55682968

Paths:        % tm_act     Kbps      tps    Kb_read   Kb_wrtn
Path1            0.0       0.0       0.0          0         0
Path0            0.3      46.3       3.7   180755051  55682968
hostname:/:$

 

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GLSCISSORARRAY(3G)						   OpenGL Manual						GLSCISSORARRAY(3G)

NAME
glScissorArray - define the scissor box for multiple viewports C SPECIFICATION
void glScissorArrayv(GLuint first, GLsizei count, const GLint *v); PARAMETERS
first Specifies the index of the first viewport whose scissor box to modify. count Specifies the number of scissor boxes to modify. v Specifies the address of an array containing the left, bottom, width and height of each scissor box, in that order. DESCRIPTION
glScissorArrayv defines rectangles, called scissor boxes, in window coordinates for each viewport. first specifies the index of the first scissor box to modify and count specifies the number of scissor boxes to modify. first must be less than the value of GL_MAX_VIEWPORTS, and first + count must be less than or equal to the value of GL_MAX_VIEWPORTS. v specifies the address of an array containing integers specifying the lower left corner of the scissor boxes, and the width and height of the scissor boxes, in that order. To enable and disable the scissor test, call glEnable() and glDisable() with argument GL_SCISSOR_TEST. The test is initially disabled for all viewports. While the test is enabled, only pixels that lie within the scissor box can be modified by drawing commands. Window coordinates have integer values at the shared corners of frame buffer pixels. glScissor(0,0,1,1) allows modification of only the lower left pixel in the window, and glScissor(0,0,0,0) doesn't allow modification of any pixels in the window. When the scissor test is disabled, it is as though the scissor box includes the entire window. ERRORS
GL_INVALID_VALUE is generated if first is greater than or equal to the value of GL_MAX_VIEWPORTS. GL_INVALID_VALUE is generated if first + count is greater than or equal to the value of GL_MAX_VIEWPORTS. GL_INVALID_VALUE is generated if any width or height specified in the array v is negative. ASSOCIATED GETS
glGet() with argument GL_SCISSOR_BOX glIsEnabled() with argument GL_SCISSOR_TEST SEE ALSO
glEnable(), glViewport(), glViewportIndexed(), glViewportArray() COPYRIGHT
Copyright (C) 2010 Khronos Group. This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1.0, 8 June 1999. http://opencontent.org/openpub/. AUTHORS
opengl.org opengl.org 06/10/2014 GLSCISSORARRAY(3G)
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