May 2, 2018 | IBM i

IBM i Storage: 5 Ways to Reclaim Storage Space to Increase Performance


In a previous post, we discussed how hardware and storage maintenance affects the performance of your IBM i data. In this post, we’ll focus on how to reclaim IBM i storage space using maintenance tasks to increase performance.


We all know that users expect their data to be returned in milliseconds. If users wait even a few seconds, they become impatient. If they wait too long, they go somewhere else and you lose business. High transaction volumes only magnify the problem. Keeping your storage space lean is one way to help ensure that your storage can meet the demands of your business.


Here are five ways that you can reclaim IBM i storage space to increase your systems performance.

#1: Keep Journals and Journal Receivers Lean

Journals are important for companies who want to track changes to critical files for audit purposes or who want to replicate data to a high availability environment. Journals track the before and after history of adds, deletes, and changes, along with other pieces of information about when the files are accessed and who accessed them. All this journaled data increases the amount of IBM i storage space required. It’s important to manage the size of your journals and journal receivers, to minimize their impact on storage performance.


Journal Receivers impact storage performance and size in several ways, including the thresholds you set for the size of your receivers, how journal data is written to storage, and when journal receivers are deleted from storage. Since journal receivers can grow quickly, it’s important to implement good management practices to increase storage utilization and efficiency, and to help keep your system operating at its peak.


One way to help keep your storage optimized is to have the system automatically clean up journal receivers which you no longer need. You can decide whether to allow your IBM i to automatically manage your journal receivers when you are setting them up. This simplifies the management of your journals, by having the system determine when to add new journal receivers and when to delete old receivers.


However, you need to use caution if you are using journals for replication purposes. The IBM i is not capable of determining if your journal receiver entries have all been applied to the target system before it deletes a receiver. So, you will need to be cautious with automatic journal management when using high availability (HA) software. But being cautious doesn’t mean you shouldn’t manage your journals and journal receivers. It just means that you should know how long your replication takes and ensure that your source and target systems are in sync before you delete old journal receivers (many HA packages make this easier by managing their journal receivers for you).


Despite having to keep an eye on when and how journals and journal receivers are managed, IBM i’s automatic journal management features will help keep your disks humming, your storage lean, and your users happy.

#2: Perform Regular File Maintenance

Keeping files and records that you don’t need is a waste of storage space and can have a negative effect on your storage performance. Companies often forget to clean up the files they no longer need, including temporary files, work files, old copies of files that were taken before a file change, etc. There’s also a storage issue with excessive file records, where companies keep records going back to the early 2000s or before, when their processing and auditing needs may only dictate keeping old data for a few years.


Not only does keeping files and records you don’t need have a negative impact on your storage performance, it also increases backup windows and the cost of backup media. Media cost for excessive files and records can be measured either in additional tapes used (if backing up to tape) or additional storage used when backing up data via disk-based backup, vaulting, or SAN-to-SAN replication. Unnecessary storage usage can have real costs.


Instead, consider creating archive files, which you can save and remove from your system, as needed. You can save these archives to physical or virtual tape in the event that they need to be restored, and then remove them from your system storage when they are no longer needed.


Companies often neglect to clean up their old spool files and save files (SAVFs). After you apply PTF’s you should delete the PTF SAVF from your system. You don’t need to save the SAVFs from old OS/400 and IBM i 5.4, 6.1, 7.1 or 7.3 PTFs, either, and they can be deleted. Users are notorious for running a report and leaving the spool file sitting on the system when they are done. Deleting old SAVFs and spool files will help ensure that your storage is performing at maximum efficiency.


Clearing temp and work files is another thing you can do to reclaim storage space. Many times, developers will make copies of large production files to do testing. Having multiple developers, who each create multiple copies of files to work against can increase storage space quickly. Ensuring that temp files, work files, and test files are removed when they are no longer needed can help keep your system lean.

#3: File Reorganization After the Clean up

Deleting unneeded files will help improve the performance of your system, but there is another step you should take that will make additional improvements. Reorganize your files. When files are written to storage, the system determines where to put the data, and the bytes get spread out across the storage sectors for data load balancing. As records are deleted, empty spaces are left behind on the disk. File reorganization moves the data around in your storage pool and fills in the gaps, moving the empty space to the end of the file where it can be reclaimed and given back to the system. Reorganization is particularly valuable for files that contain a lot of deleted records or are regularly updated.


You used to have downtime to reorganize files, but downtime for file reorganization is increasingly a luxury in today’s 24x7x365 world. To be able to reorganize while still providing near constant availability, IBM added Reorganization while active capabilities to the Reorganize Physical File Member (RGZPFM) command. You need to use journaling to reorganize an active file. Reorg while active allows the system to use the journals to capture the changes the users are making and to process them as the data is being reorganized. In the past, this feature was sold by 3rd party vendors. Now you get it for free with your IBM i.

#4: Clearing Logs

If you’ve ever looked at the QSYSOPR message queue than you know how many messages are generated on the IBM i. Messages and system logs are helpful when trouble shooting. But, keeping those messages and log files can affect performance. A normal part of IBM i System Administration is to clear logs on a regular basis.


Not only is it important to review and clear logs to keep the system performing better, it also helps to clear system messages so that important issues don’t get lost. If an Administrator needs to review pages of messages to find issues, it’s easy to miss something. By keeping logs and message queues clean, it’s easier to find the real problems when they happen. Reviewing logs and message queues for pending issues is another area where IBM i monitoring programs like SEA’s absMessage come in handy. Your monitoring package can examine your message queues and logs for you, and then alert you when it sees any unusual situations you told it to monitor for. Monitoring packages can also look for other issues, including the state of your hardware, disk utilization, CPU utilization, and other unusual situations that can indicate application or data errors.


It’s important to find a balance between meeting audit requirements and having too much data. Finding a sweet spot will help improve the performance of your system and reduce the costs.

#5: Don’t forget the IFS

Companies sometimes forget to clean up their IFS files. The IFS can support a lot of file types and as a result there is a lot of data that gets stored here. For example, email and fax packages can leave a lot of work files that can fill IFS storage, if they’re not regularly maintained. It’s just as important to keep your IFS lean as it is your traditional IBM i libraries and files. Just like your traditional IBM i objects, there are often excess files that you can delete to help keep the system running smoothly.


Keeping your system running smoothly also requires that you monitor what is happening and use IBM’s utilities to clean house,. SEA offers solutions that can help alert you to storage issues before they affect your users. Feel free to contact us at SEA for more information on reclaiming storage space to increase performance.