---------- Forwarded message ---------- From: Shai Hess <mfnetd...@mfnetdisk.com> Date: Wed, Feb 8, 2012 at 11:20 AM Subject: New documentation about MF emulation and MFNetDisk. To: shai.h...@gmail.com
** HI, I add documentation about MF emulation and MFNetDisk. Shai * MF emulation and MFNetDisk * I want to thank the user from Spain who motivates me to write about this subject. MFNetDisk uses MF emulation (ZPDT) the same as it use real MF. So, MFNetDisk enables user to share emulated tapes and disks among many real MF and many emulated MF. For tapes emulation just adds virtual tapes and you can share the MFNetDisk tapes for all type of MF. For disks we must talk about replication and emulation 3390 disks. For emulation the story is simple as for tapes. Just define virtual 3390 to MFNetDisk and you can share the virtual disks among real MF and emulated MF. Using the emulation the performance is OK but is not as FICON performance. MFNetDisk with its stacks CCW feature improved the performance dramatically but still it is almost FICON but is not the same. About replication, MFNetDisk enable replication of real disks to MFNetDisk pc files mirrors. Replication does not cause delay to the MF real disks nor degradation in the performance of the MF itself and its real disks. CPU overhead is almost zero. If a few of your MF real disks crashes you can use the mirror as 3390 disks using MFNetDisk to emulate its mirror as it was real disks. If all your MF system crashed, using MFNetDisk to emulate all your MF disks is limited because MFNetDisk can not IPL emulated 3390 disks pc devices by itself. In this case the best can be to run MF emulation (ZPDT) to take control on MFNetDisk disks which the pc file type AWS is fully supported by the emulated MF software. In his case the performance is great using the PC IO performance. Also the MF emulated can IPL the AWS pc file created by MFNetDisk as it was MF emulated disks. So, here is what needs to be done for enabling this case. Example: Your real MF uses 256 (any numbers is OK) real disks. SYSTEM IPL able disks are also included. The MF device numbers are A00-AFF. Your MF emulator is IBM ZPDT. • Add 256 MFNetDisk replication pc devices. • These pc devices enabling async mirroring of your real disks without degradation in your MF performance. • This replication pc device will contain as source disks, the IP of the real MF and the device number of real 3390 disk in your real MF. • MFNetDisk will collect updates to the real disk and take care of sync all these tracks to its defined target mirrors. • Add mirror pc file type AWS as target mirror which will contain the exact data as the real 3390 disk. • MFNetDisk supports AWS, compression pc file and MPC file. • AWS format is supported pc files by all emulated MF. • Add these mirrors to all your replication pc devices which mirrors yours real 3390 to MFNetDisk pc file type AWS. • This enables ZPDT to support these pc files as attached emulated 3390 disks. • MF emulation can not work with real 3390 disk but use very well emulated 3390 AWS disks which support by MFNetDisk and by many emulated MF. • This MFNetDisk configuration will be called NORMAL configuration because this configuration will be active all the times when MF and its real disks operate fine. • Create another copy of MFNetDisk which will be active in case of DR condition. This new configuration will be called DR configuration. • The DR configuration will be active when emulated MF is active after disaster when the real MF stopped to function. • This DR configuration will keep all the tracks which were updated in the emulated MF in the time of the DR. • When the real MF become active OK, we can use the DR configuration to sync all tracks from the AWS disks to the real disks in case that the 3390 are operational and contained the sync data until the point of the disaster. • The DR configuration will contained the AWS as source disk and the real disk as target mirror. • In DR configuration for each write to the AWS disks, MFNetDisk will maintain tracks map of all the tracks need to be sync for the real disk, when the real disk become active. • This DR MFNetDisk copy will use the AWS in the ZPDT as source 3390 disk and the real 3390 as target mirror for the source disk. • The DR and NORMAL configuration will use the replication pc device MFNetDisk feature keep the best performance to the ZPDT and for the real MF without and performance degradation using the MFNetDisk. • If you like to create sync point, validate that all tracks of the mirrors are sync with the real disks. • Defined the AWS pc files as locally attached files to ZPDT. Do not forget to add the system disks which will be used to IPL the ZPDT with your real MF OS disks. • So, to summarize, you run your NORMAL configuration with MFNetDisk replication always when your MF is OK. • If your site real MF stopped to function and you like to use the emulated MF to work in no time with all the real MF data, some actions are required. • Check that your ZPDT contained the entire AWS pc files defined in it. • Verify that your DR configuration defined as replication pc devices with the source 3390 is the AWS pc file and the target mirror is the real disk which is defined with the IP of the MF and the MVS device number in your real MF. • Start the ZPDT. IPL your AWS pc file which contained the replicated pc file of your system disk (example ZXXRES). • Start MFNetDisk with DR configuration to trace all your updates to the AWS disks while the ZPDT is operational and the real MF is dead. • If the real MF becomes active, you can activate your real MF pc files mirrors and MFNetDisk will start to copy all the tracks, and only the tracks which were updated. • You can continue to work with ZPD until your real 3390 are sync with the AWS disks. • When you like you can return to normal operation in real MF, and just validate that MF configuration change to NORMAL configuration to be ready for another DR condition. Thanks, God bless you. Shai Hess, MFNetDisk product. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: INFO IBM-MAIN
