On Wed 30-11-11 21:29:28, Wu Fengguang wrote:

quoted

cat /etc/udev/rules.d/60-readahead.rules
# 
 
 

# Rules to set an increased default max readahead size for s390 disk 
devices 
 

# This file should be installed in /etc/udev/rules.d 
 
 

# 
 
SUBSYSTEM!="block", GOTO="ra_end" 

ACTION!="add", GOTO="ra_end" 

# on device add set initial readahead to 512 (instead of in kernel 128) 

KERNEL=="sd*[!0-9]", ATTR{queue/read_ahead_kb}="512" 

KERNEL=="dasd*[!0-9]", ATTR{queue/read_ahead_kb}="512" 

So SLES (@s390 and maybe more) is already shipping with 512kb
readahead size? Good to know this!

  SLES (and openSUSE) since about 2.6.16 times is shipping with 512kb
readahead on everything... With some types of storage it makes a
significant difference.

								Honza
-- 
Jan Kara [off-list ref]
SUSE Labs, CR

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