LDL is kind of a misnomer. It only means that the disk is all blocked consistently (at 4K), which is more good than bad.
Last I recall, you could still boot from LDL just fine. (It is the original layout for Linux/390 CKD.) Last time I measured, I was disappointed to not find significant performance boost with the DIAG driver. That's surprising because in theory there would be a significant win with DIAG. (It is the only mode used by CMS, which gave up CCW disk I/O decades ago.) But there was no penalty. I recommend it. -- R; <>< On Jan 3, 2011 11:01 AM, "Samir Reddahi" <samir.redd...@securex.be> wrote: > We have currently a couple of DB2 machines with logical volumes on MOD-9 > ECKD disks. On our DB2 production server we have mdcache enabled for the > logical volumes that contains the DB2 data. The other servers have mdcache > disabled. > > We already use the DIAG driver for the swap disks and the VDISKs. Now I'm > looking if it is interesting to switch the other disks to DIAG too. > > Disks are currently formatted with cdl. I've read that cdl and DIAG can't > work together so the disks have to be formatted to another format. We will > be migrating to a new Z196 and a new DS8800, so I can use the downtime to > switch the logical volume to an LV with DIAG disks > > a couple of questions: > > 1) Are there any disadvantages of formatting disks as ldl instead of cdl? > 2) Is it true that /boot directory has to be located on a non-DIAG disk? > 3) What kind of performance improvement can I expect from a move to DIAG > dasd > 4) Any disadvantages of using DIAG instead of ECKD? > > > > Best regards > Samir Reddahi > > System Engineer | Systeem MF, AS400, DBA Operations > T +32 9 235 61 09 | M +32 478 80 68 30 > samir.redd...@securex.be > > www.securex.be > > - Confidentiality Notice - > > This communication and the information it contains is intended (a) for the person(s) or organization(s) > named above and for no other person or organization, and (b) may be confidential, legally privileged and > protected by law. Unauthorized use, copying or disclosure of any of it may be unlawful! If you receive > this communication in error, please notify us immediately, destroy any copies and delete it from your > computer system. Please consult our disclaimer on our site www.securex.eu > 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/
