Patch Name: PHKL_22310

Patch Description: s700 10.20 VxFS I/O throttling for slow devices

Creation Date: 00/09/12

Post Date:  00/09/22

Hardware Platforms - OS Releases:
	s700: 10.20

Products: N/A

Filesets:
	JournalFS.VXFS-BASE-KRN

Automatic Reboot?: Yes

Status: General Release

Critical: No

Path Name: /hp-ux_patches/s700/10.X/PHKL_22310

Symptoms:
	PHKL_22310:
	(SR: 8606157903   CR: JAGad27233)
	Systems with heavy I/O to slow devices may sometimes
	experience slow response time for processes trying to
	access the respective device.

Defect Description:
	PHKL_22310:
	(SR: 8606157903   CR: JAGad27233)
	The method used by VxFS filesystems for writing sequential
	data is to asynchronously write data up to a limit and when
	that limit is met, to delay-write the remaining data.  This
	data is flushed periodically.  The adverse effect of having
	a large amount of delayed-write data in the buffer cache is
	that it can potentially flood the device with requests.

	Resolution:
	In order to slow the amount of I/O requests made to
	devices that cannot keep up with demand a throttling
	mechanism will be put in place for flushes from the
	buffer cache to VxFS files that will prevent a device
	from being overloaded.

SR:
	8606157903

Patch Files:
	/usr/conf/lib/libvxfs_base.a(vx_chain.o)

what(1) Output:
	/usr/conf/lib/libvxfs_base.a(vx_chain.o):
		vx_chain.c $Date: 2000/09/11 14:58:05 $ $Revision: 1
			.7.98.7 $ PATCH_10.20 (PHKL_22310)

cksum(1) Output:
	3493577775 5492 /usr/conf/lib/libvxfs_base.a(vx_chain.o)

Patch Conflicts: None

Patch Dependencies:
	s700: 10.20: PHKL_16750

Hardware Dependencies: None

Other Dependencies: None

Supersedes: None

Equivalent Patches:
	PHKL_22311:
	s800: 10.20

Patch Package Size: 60 KBytes

Installation Instructions:
	Please review all instructions and the Hewlett-Packard
	SupportLine User Guide or your Hewlett-Packard support terms
	and conditions for precautions, scope of license,
	restrictions, and, limitation of liability and warranties,
	before installing this patch.
	------------------------------------------------------------
	1. Back up your system before installing a patch.

	2. Login as root.

	3. Copy the patch to the /tmp directory.

	4. Move to the /tmp directory and unshar the patch:

		cd /tmp
		sh PHKL_22310

	5a. For a standalone system, run swinstall to install the
	    patch:

		swinstall -x autoreboot=true -x match_target=true \
			-s /tmp/PHKL_22310.depot

	By default swinstall will archive the original software in 
	/var/adm/sw/patch/PHKL_22310.  If you do not wish to retain a
	copy of the original software, you can create an empty file
	named /var/adm/sw/patch/PATCH_NOSAVE. 

	WARNING: If this file exists when a patch is installed, the 
	         patch cannot be deinstalled.  Please be careful
		 when using this feature.

	It is recommended that you move the PHKL_22310.text file to 
	/var/adm/sw/patch for future reference.

	To put this patch on a magnetic tape and install from the
	tape drive, use the command:

		dd if=/tmp/PHKL_22310.depot of=/dev/rmt/0m bs=2k

Special Installation Instructions:
	This patch depends on base patch PHKL_16750 .
	For successful installation, please ensure that PHKL_16750
	is in the same depot with this patch, or PHKL_16750  is
	already installed.