Unused VDISK is not quite for free, but close, maybe. VDISK costs real dedicated CP memory and real CP paging disk.
For each VDISK, CP dedicates unpageable memory to the VDISK's page/segment tables. Not clear from the z/VM Admin guide whether CP dedicates 2050 pages per each VDISK of <= 1GB in size (in which case the CP overhead per VDISK is 0.78% and higher depending on VDISK size); or whether CP dedicates a fraction of 2050 pages proportional to each VDISK's size. I think you need to give real paging disk to CP to hold all those VDISK pages should CP decide it needs to store them out on disk. If the CP paging space is never to be used then at least it's not those Linux guests wasting that real disk space. VDISK has its pluses and minuses. -------------------------------------------------------- This e-mail, including any attachments, may be confidential, privileged or otherwise legally protected. It is intended only for the addressee. If you received this e-mail in error or from someone who was not authorized to send it to you, do not disseminate, copy or otherwise use this e-mail or its attachments. Please notify the sender immediately by reply e-mail and delete the e-mail from your system. -----Original Message----- From: Linux on 390 Port [mailto:[EMAIL PROTECTED] On Behalf Of Rob van der Heij Sent: Thursday, January 25, 2007 3:51 PM To: [email protected] Subject: Re: General question on swap file placement ...... ---<snip>-- If the disk space is never to be used then it's a waste to take real disk space. Unused VDISK is for free. Rob -- Rob van der Heij Velocity Software, Inc http://velocitysoftware.com/ ---------------------------------------------------------------------- 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
