Doug Cutting wrote:
The linux
kernel dynamically increases the readahead window based on the access
pattern: the more you read sequentially, the larger the readahead window.
Sorry, it appears that's in 2.6.23, which isn't yet broadly used.
http://kernelnewbies.org/Linux_2_6_23#head-102af265937262a7a21766ae58fddc1a29a5d8d7
In the meantime, on Linux, one can set both the kernel's readahead
buffer size and the device's. These are additive: the first determines
what requests will be made to the device, the second determines how much
beyond that the device will attempt to read.
# set kernel read-ahead buffer to 1MB
echo 1024 > /sys/block/sda/queue/read_ahead_kb
# set device read-ahead buffer to 1024 sectors
hdparm -a1024 /dev/sda1
I don't know how much these actually help things...
Doug
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