Re: HSM RECYCLE INFLUENCE
To add on to Lizette's comments and using her example below, if vol1-4 are in a connected set (i.e. continued volumes), *ALL* volume in the connected set must meet the threshold or *NONE* will be selected for recycle. E.G. the connected set consists of 4 volumes. VOL1 50% VOL2 20% VOL3 15% VOL4 1% Any RECYCLE PERCENTVALID < 50 will result in *NONE* of the volumes being selected for recycle. There are 2 ways around this. 1) Break the connection by recalling/deleting the "spanning" dataset. This dataset can be found by HSEND LIST TTOC(volume) and will either be the 1st or last dataset listed and recycle the "disconnected" volume. 2) Run RECYCLE EXECUTE VOLUME(any volume in the connected set). This will cause any gaps in the connected set to be eliminated and all of the tapes in the connected set will *APPROACH* 100% utilization. This may or may not release one or more tapes from the connected set. In the example above this would result in 1 volume of 86% instead of 4 volumes with an average utilization of 22%. There are a number of SETSYS parameters in addition to PARTIALTAPE(MARKFULL) that affect this as well. There is more to this topic than can be covered in a short email. I suggest reading the DFSMS/hsm Storage Administration guide: SC23-6871-02z/OS DFSMShsm Storage Administration (z/OS 2.1). HTH, PARTIALTAPE(REUSE) vs PARTIALTAPE(MARKFULL) When using a virtual tape system, IBM usually recommends using PARTIALTAPE(MARKFULL). RECYCLE You (or automation) need to issue the RECYCLE command, it is not automatic. Also, if you want HSM to recycle multiple tape volumes onto one, you will need to use a GENERIC recycle command, for example: Use 'ALL' to recycle both ML2 and backup tape volumes: HSEND RECYCLE ALL PERCENTVALID(20) EXEC Use 'ML2' to recycle only ML2 tape volumes: HSEND RECYCLE ML2 PERCENTVALID(20) EXEC Use 'BACKUP' to recycle only backup tape volumes: HSEND RECYCLE BACKUP PERCENTVALID(20) EXEC Suggested numbers for ML2RECYCLEPERCENT are 20% or 30%. This allows more volumes to become eligible to be recycled onto fewer volumes at the same time. For example: VOL1 50% VOL2 20% VOL3 15% VOL4 1% With ML2RECYCLEPERCENT(1), only VOL4 will be recycled. The next time you run RECYCLE again, the same tape would be recycled again and again. With ML2RECYCLEPERCENT(25), VOL2, VOL3 and VOL4 would be recycled. The resulting percent used for the output tape will become 36%, so, that tape will not be recycled again the next time around. MAXRECYCLETASKS(nn). Each recycle task requires an output tape. If you allow 5 recycle tasks to run concurrently and have 5 tapes to recycle, you will land up with 5 recycled tapes (no reduction). If you increase the time between recycles, this should also allow more tapes to become eligible to be recycled onto fewer tapes. If you have migrated to a new tape technology, the REUSE CAPACITY (this is an average) will be incorrect leading to unneeded recycles. With time however, the REUSE CAPACITY will better reflect the reality of your new environment. This email � including attachments � may contain confidential information. If you are not the intended recipient, do not copy, distribute or act on it. Instead, notify the sender immediately and delete the message. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
Re: HSM RECYCLE INFLUENCE
When we went to pure virtual tape, this is what we got back from IBM DFHSM L2: PARTIALTAPE(REUSE) vs PARTIALTAPE(MARKFULL) When using a virtual tape system, IBM usually recommends using PARTIALTAPE(MARKFULL). RECYCLE You (or automation) need to issue the RECYCLE command, it is not automatic. Also, if you want HSM to recycle multiple tape volumes onto one, you will need to use a GENERIC recycle command, for example: Use 'ALL' to recycle both ML2 and backup tape volumes: HSEND RECYCLE ALL PERCENTVALID(20) EXEC Use 'ML2' to recycle only ML2 tape volumes: HSEND RECYCLE ML2 PERCENTVALID(20) EXEC Use 'BACKUP' to recycle only backup tape volumes: HSEND RECYCLE BACKUP PERCENTVALID(20) EXEC Suggested numbers for ML2RECYCLEPERCENT are 20% or 30%. This allows more volumes to become eligible to be recycled onto fewer volumes at the same time. For example: VOL1 50% VOL2 20% VOL3 15% VOL4 1% With ML2RECYCLEPERCENT(1), only VOL4 will be recycled. The next time you run RECYCLE again, the same tape would be recycled again and again. With ML2RECYCLEPERCENT(25), VOL2, VOL3 and VOL4 would be recycled. The resulting percent used for the output tape will become 36%, so, that tape will not be recycled again the next time around. MAXRECYCLETASKS(nn). Each recycle task requires an output tape. If you allow 5 recycle tasks to run concurrently and have 5 tapes to recycle, you will land up with 5 recycled tapes (no reduction). If you increase the time between recycles, this should also allow more tapes to become eligible to be recycled onto fewer tapes. If you have migrated to a new tape technology, the REUSE CAPACITY (this is an average) will be incorrect leading to unneeded recycles. With time however, the REUSE CAPACITY will better reflect the reality of your new environment. Hope this helps. Lizette > -Original Message- > From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On > Behalf Of Anthony Fletcher > Sent: Wednesday, March 02, 2016 4:20 PM > To: IBM-MAIN@LISTSERV.UA.EDU > Subject: HSM RECYCLE INFLUENCE > > We are using a VTS with the virtual tapes defined as 3490s, and we are using > the recommended 'Mark TAPE Full' option. That's all well and good. > It does, however, mean that there are a lot of 'tapes' and many of those may > have a mixture of valid and no-longer-valid data sets - a call for Recycle. > The VTS is probably under configured, but that's life, and its a financial > institution so they keep everything for 7 years, and are paranoid about > keeping things so there is really too much data floating around that has to > continue to float around. > > HSM can decide that it should do recycles, and if it does decide, then it will > according to its built in algrorithm. > > However, we find that the algorithm makes decisions based on the WHOLE set of > volumes that it knows about. That is OK, except that if there are a lot of > huge data sets that have been migrated, and they used full tapes (and probably > more than one tape). That skews the data to a higher than the overall usage > figure, and it doesn't conclude that recycles are needed. We can of course > initiate manual recycles but working out which ones to choose is a pain. So we > are looking at writing something to automate that. We are looking at reading > the OCDS and using that to select which volumes (eg excluding the big ones) > and then issue the RECYCLE commands. > > It seems that HSM ought to be able to automatically do the selection of which > volumes to do in a way that works for us. > > So the question is whether we can influence the recycle trigger point > automatically to select what to recycle? e.g. tell it to ignore the full > volumes and only assess based on the rest of the volumes or something like > that. > > We used to have real tapes and it didn't matter if the algorithm resulted in > few recycles, but with the VTS we need to release the space in the VTS to stay > alive. > -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
Re: HSM RECYCLE INFLUENCE
With our VTS, we found ourselves in the position where the default automatic DFHSM recycle was unable to keep up with scratch cartridge release that was needed to maintain the required scratch count, which was putting the whole VTS environment at risk (90+% of which was consumed by DFHSM migration). And VTS reclaim was also struggling to keep up (the MUCH more dangerous aspect), DFHSM recycle & VTS reclaim were pretty much running 24x7 trying to perpetually de-honeycomb the whole environment, and fighting a losing battle. Hard to tell from your description whether you are asking this, because you are finding yourself in that position too. If you are, then it is a potentially solveable problem, but it aint straightforward, and do-ability and effectiveness may be heavily dependant on a very good understanding of your physical VTS arrangement (e.g. grid setup, virtual drive arrangements, etc.), and the ability to 'adjust things' where necessary. Reading the OCDS and determining the 'best' DFHSM recycle candidates is a good first step of that journey (to ignore any chained volumes, thus concentrating recycle focus on the lowest utilised singletons to free up), driving as many manual recycles as required. Depending on how dire a situation you are in, that may be enough by itself, but obviously manual recycles are single streamed, which is the slight downside, although you can mitigate that to a certain extent by spreading across multiple LPARs. On 2 March 2016 at 23:20, Anthony Fletcher wrote: > We are using a VTS with the virtual tapes defined as 3490s, and we are > using the recommended 'Mark TAPE Full' option. That's all well and good. > It does, however, mean that there are a lot of 'tapes' and many of those > may have a mixture of valid and no-longer-valid data sets - a call for > Recycle. The VTS is probably under configured, but that's life, and its a > financial institution so they keep everything for 7 years, and are paranoid > about keeping things so there is really too much data floating around that > has to continue to float around. > > HSM can decide that it should do recycles, and if it does decide, then it > will according to its built in algrorithm. > > However, we find that the algorithm makes decisions based on the WHOLE set > of volumes that it knows about. That is OK, except that if there are a lot > of huge data sets that have been migrated, and they used full tapes (and > probably more than one tape). That skews the data to a higher than the > overall usage figure, and it doesn't conclude that recycles are needed. We > can of course initiate manual recycles but working out which ones to choose > is a pain. So we are looking at writing something to automate that. We are > looking at reading the OCDS and using that to select which volumes (eg > excluding the big ones) and then issue the RECYCLE commands. > > It seems that HSM ought to be able to automatically do the selection of > which volumes to do in a way that works for us. > > So the question is whether we can influence the recycle trigger point > automatically to select what to recycle? e.g. tell it to ignore the full > volumes and only assess based on the rest of the volumes or something like > that. > > We used to have real tapes and it didn't matter if the algorithm resulted > in few recycles, but with the VTS we need to release the space in the VTS > to stay alive. > > -- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
Re: HSM RECYCLE INFLUENCE
On 3/2/2016 6:19 PM, Anthony Fletcher wrote: We are using a VTS with the virtual tapes defined as 3490s, and we are using the recommended 'Mark TAPE Full' option. That's all well and good. It does, however, mean that there are a lot of 'tapes' and many of those may have a mixture of valid and no-longer-valid data sets - a call for Recycle. The VTS is probably under configured, but that's life, and its a financial institution so they keep everything for 7 years, and are paranoid about keeping things so there is really too much data floating around that has to continue to float around. HSM can decide that it should do recycles, and if it does decide, then it will according to its built in algrorithm. However, we find that the algorithm makes decisions based on the WHOLE set of volumes that it knows about. That is OK, except that if there are a lot of huge data sets that have been migrated, and they used full tapes (and probably more than one tape). That skews the data to a higher than the overall usage figure, and it doesn't conclude that recycles are needed. We can of course initiate manual recycles but working out which ones to choose is a pain. So we are looking at writing something to automate that. We are looking at reading the OCDS and using that to select which volumes (eg excluding the big ones) and then issue the RECYCLE commands. It seems that HSM ought to be able to automatically do the selection of which volumes to do in a way that works for us. So the question is whether we can influence the recycle trigger point automatically to select what to recycle? e.g. tell it to ignore the full volumes and only assess based on the rest of the volumes or something like that. We used to have real tapes and it didn't matter if the algorithm resulted in few recycles, but with the VTS we need to release the space in the VTS to stay alive. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN Anthony, The trigger is PERCENTVALID. Try a higher percentage to recycle. With a VTS, maybe go 50%. CHECKFIRST can be used if you have a lot of connected sets. You can also SELECT to limit yourself to a range of tapes. You should have enough flexibility to do what you want. Regards, Tom Conley -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
