I'm also interested in peoples answer. I do it off hours on our non-prod hosts to try to minimize Linux guest cache. In our non-prod guests we run many Websphere servers with variable heap sizes. I chose to oversize the linux guests memory by a few gig to account to allow heap growth on these non-prod servers. If many of these development servers heaps grow at a time, it uses up the extra memory used by linux file cache, and then the linux swap is set up in a series of "tiered" (256M, 512M, 1024M) ZVM VDISK. The downside to VDISK, is if it gets swapped out by ZVM, the swapin period can bring the linux to a temporary halt while VDISK is swapped back in. The pause can be significant on a 1GB VDISK.
So I do it nightly on several guests, and there has been no consequence so far. The methodology I use is: /bin/sync # forces all buffered writes to disk /sbin/sysctl vm.drop_caches=3 # flushes files from memory /bin/sync # can't hurt /sbin/sysctl vm.drop_caches=0 # reset back to default /bin/sync Good luck! Jon Veencamp Federated Insurance. -----Original Message----- From: Linux on 390 Port [mailto:LINUX-390@VM.MARIST.EDU] On Behalf Of Dean, David (I/S) Sent: Thursday, August 15, 2013 9:44 AM To: LINUX-390@VM.MARIST.EDU Subject: linux cache Is there any benefit (or negative) to running a "drop_cache" periodically? ----------------------------------------------------- Please see the following link for the BlueCross BlueShield of Tennessee E-mail disclaimer: http://www.bcbst.com/email_disclaimer.shtm ________________________________ The information contained in this e-mail message is intended only for the personal and confidential use of the designated recipient(s) named above. This message may be an attorney-client or work product communication which is privileged and confidential. It may also contain protected health information that is protected by federal law. If you have received this communication in error, please notify us immediately by telephone and destroy (shred) the original message and all attachments. Any review, dissemination, distribution or copying of this message by any person other than the intended recipient(s) or their authorized agents is strictly prohibited. Thank you. ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
