> We have formated a mini disk of 285 Cylinders with : > > dasdfmt -b 4096 -n 0104 > > dev00002:/mnt# less /proc/dasd/devices > 0104(ECKD) at ( 94: 16) is dasde : active at blocksize: 4096, 51300 > blocks, 200 MB
Going over the numbers, the overhead from dasdfmt is startling. At 849,960 bytes a cylinder, your 285 cyls should yield 242,238,600 bytes. Yet formatted at 12 4k blocks per track, you only get 4096 * 51300 = 210,124,800. Right there, that's 13.26% out the window immediately. The CDL, partition, filesystem/journal overhead is really quite tiny in comparison. The larger the number of cyls for the device, the worse the ratio gets :(. >From Neale Ferguson's SCSI on Linux for zSeries presentation, it looks like he doesn't have to worry about this :). ~ Daniel ----------------------------------------------------------------------- This message is the property of Time Inc. or its affiliates. It may be legally privileged and/or confidential and is intended only for the use of the addressee(s). No addressee should forward, print, copy, or otherwise reproduce this message in any manner that would allow it to be viewed by any individual not originally listed as a recipient. If the reader of this message is not the intended recipient, you are hereby notified that any unauthorized disclosure, dissemination, distribution, copying or the taking of any action in reliance on the information herein is strictly prohibited. If you have received this communication in error, please immediately notify the sender and delete this message. Thank you. ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
