SAR Hints and Recommendations

IPL from DASD

We recommend that copies of SAR be put onto DASD. The SAR IPL records can be loaded onto DASD by the FDRSARLR program. SAR resides on the volume label track, cylinder 0 track 0, and does not take any space that could be allocated to data sets. We recommend putting copies of SAR onto several volumes on different control units. Critical time can be lost when SAR is needed and the tape cannot be found, or the only copy is locked in the system programmer's desk. Of course, keep a visible list of the volumes on which SAR has been loaded near the console.

While tape always works, you have to find the tape first!

Customizing SAR

You can use the FDRSARLR program to customize SAR for your installation (or for your disaster recovery site). The options that are displayed on the SAR menu are clear and can be overridden at run time, so they usually do not need to be customized, but it may save time to set some options to the commonly used values.

However, it is often useful to customize SAR with the console device type and console address (or addresses, up to 5). Why? If the console address is not specified in advance by FDRSARLR, SAR waits for a unit to present an ATTENTION interrupt (which is generated by a console when the ENTER or REQUEST key is pressed). SAR then issues CCWs for various types of consoles to see if this device responds to one of them. However, if you have terminals which are attached to your CPU via local non-SNA control units, anxious users pressing ENTER may receive the SAR menu instead of you. If you customize SAR with the addresses of the consoles you normally use, SAR tests them immediately without waiting for an ATTENTION.

If you are reading this, your system is down, and you do not get the SAR menu after IPLing SAR, you probably have terminals or other devices that are presenting ATTENTION. You may have to reset and/or disable the control units of those devices via switches on their control panels before retrying SAR. You may also need to disable or reset other communication controllers (such as 3745s) and channel-to-channel adapters (CTCs) as these may also generate ATTENTION.

Retain tape between restores

High-capacity tape drives can hold the backups of many DASD volumes. Almost all installations stack multiple backups on tape to get the best utilization from their tape cartridges; ABR backups are automatically stacked on tape.

Normally SAR rewinds and unloads each input tape when it completes the restore.

If you are restoring from a backup tape containing multiple backups, and plan to restore another backup on the same tape, you can specify that SAR should NOT unload the tape at the end of the restore, by:

Create a portable copy of SAR after electronic install

With electronic installs, a “physical” tape does not exist. To create a “physical” tape with an IPLable version of SAR on it, refer to the Load SAR to Tape from ICL Library Example section.

ABR backup tapes

SAR supports restores from any file on an ABR full-volume backup. To be prepared to run SAR to restore ABR backups, you should run a weekly FDRABRP “PRINT CATLG” report, that shows the tapes volumes and file numbers for the full-volume backups of every DASD volume. These hard copy reports should be readily available to the Operations staff so that the proper tapes can be fetched and mounted. If you need to run SAR and the PRINT CATLG report is not available, you can also get the same information from the FDR305 messages in the listing of the last FDRABR job that created the full-volume backups required (but only if the printout is available in hard copy).

You must specify the file number as “fff” (specify all 3 digits) in the SAR option:

INPUT TAPE UNIT=uuu,fff

The number that you specify is the FILE value from the PRINT CATLG or FDR305 message, as shown below. This is the logical file sequence number (relative to the first volume in a multi-file, multi-volume tape aggregate); it may not be the physical file number on the current tape. SAR matches the “fff” value against the header labels of the tape mounted until that file is found.

Sample PRINT CATLG REPORT:

Sample ABR messages:

Volume serial reply

Sometimes users are not sure what volume serial to specify for a SAR restore. The correct serial is the current volume serial of the output volume to which you are restoring. SAR verifies that volume serial before allowing the restore to proceed. If you enter the wrong serial, SAR displays the actual serial for verification.

If you specify the SAR option CPY=Y, then SAR changes the volume serial of that DASD volume to the DASD serial contained on the backup tape being restored (if different). If CPY=N is specified, then the serial of the output DASD volume is retained. If you specify CPY=C, SAR returns to the VOLUME SERIAL= prompt to ask for a new volume serial for the output DASD volume. However, if the backup being restored contains VSAM data sets or is an SMS-managed volume, the DASD volume may not be usable by z/OS if CPY=Y is not used (unlike FDR, SAR does not check for these conditions). CPY=Y is usually the appropriate choice.

For example, if you backed up volume SYS001 to tape and you are now restoring to volume serial SPARE1, you specify:

VOLUME SERIAL=SPARE1,CPY=Y

And the volume is labeled SYS001 after the restore is complete.

If the output volume does not contain a valid volume label nor is brand new (uninitialized), enter 6 blanks or one asterisk (*) for the response to the volume serial prompt and SAR allows the restore without verifying the serial. This allows you to do a restore without running ICKDSF to preinitialize the volumes. If the volume contains no volume label, you may get a SAR I/O error message; it can be ignored by pressing ENTER to continue.

Stand-Alone backup

SAR can do stand-alone backups. Stand-alone backup allows more flexibility in a disaster situation. For example, if the operating system is unavailable due to an HDA failure, and you have no spare volumes to restore required system volumes to, you can use SAR to dump a less critical volume before overwriting it from the backup of the critical volume. You can restore the backup of the less critical volume later when the HDA problem has been repaired (be sure to carefully record the serials of the tape volumes used for the backup). Without stand-alone backup, someone may have to decide what volumes can be sacrificed in order to get the system back, or wait for the repair to be completed (which may be hours).

Even if spare volumes are available, can you be sure that no one has used it for “short-term” storage? To be sure, you can do a stand-alone backup of the spare volume before you do that critical stand-alone restore.

Problem determination

If the IPL of SAR fails, it may be a hardware problem or a configuration problem. To quickly determine if it is a hardware problem, try to IPL stand-alone ICKDSF from tape, or IBM's stand-alone memory dump (SADMP) from DASD. However, both of these require preparation while your z/OS system is still up.

If the IPL of SAR completes (IPL COMPLETE or LOAD COMPLETE messages) but the SAR menu does not appear on your console when you press ENTER (or on the console you configured as the default console for SAR), display the current PSW (you may have to STOP the CPU to see the PSW). If it does not end in x’FFFF’, then there may be a hardware problem with the console, or it may be that another locally-attached terminal has pressed ENTER before you did and has received the SAR messages. If it does end in x’FFFF’, then SAR is not recognizing your console as a supported SAR console.

IPL from standard label tape

There is often confusion when you IPL SAR from a SL tape. This is why we recommend that you copy SAR to a NL (unlabeled) tape or DASD volume to make IPL simpler. However, if you must IPL from an SL tape:

• The first four IPL attempts fail. This is because they encounter the VOL1, HDR1, HDR2 tape labels, and the tape mark that follows them. Each IPL moves past one record or tape mark. The fifth IPL reads the SAR IPL text in the data file and is successful.
• Depending on your CPU type, you get various error messages when those first four IPL attempts fail. If your CPU displays the CSW or status, the channel status is probably 0E00 or 0200 for the first three attempts (unit check) and 0D00 or 0100 for the fourth (unit exception, caused by the tape mark). On some CPUs you must allow 10-15 seconds between IPL attempts; if you attempt to reIPL too quickly, some CPUs fail the IPL attempt without moving the tape.

Sample SAR screen after restore is complete: