I'm an old user of several backup programs (some enterprise market, some personal) who has mainly be using Apple's TimeMachine to backup multiple computers including one having Window's "disks'' (50+Gb HFS+ files) virtualized under Parallels. Needless to state, using TimeMachine has certain shall-we-say "challenges", especially the lack of the ability to consolidate backing up multiple machines to a single archive and the need to back up an entire multi-Gb file if a single byte changes.

Deduplication (and therefore, QRecall) should be my friend, so I've jumped onto the Beta hoping to become a user. But QRecall pales in comparison to TimeMachine in one important aspect: Impact of QRecall on system usability.

I rarely notice when Time Machine is doing it's hourly stuff,, but QRecall severely impacts my computer. Suddenly, my Mac's operations like web browsing, file manipulation -- anything which requires disk access -- slow down and I wonder "What the heck's going on?" and the answer is QRecall. Especially for operations like compacting an archive or verifying.

(1) Time Machine sets the "use low-priority I/O" flag which gives precedence to non-Time Machine I/O, thereby lessening the impact of a backup. Could this be made a settable option in QRecall?

(2) There are times I *really* need all the performance I can get from my Mac (like when running Windows in a virtualized environment) and many of QRecall's operations take *hours* to complete. I've learned the hard way quitting QRecall in the mist of a long operation (like a compact) may have dire consequences!
Could we *please* have a "Pause" button? Something which would pause QRecall until a "Resume" button is pressed? (OK, it could nag the user every X minutes when paused to resume so its paused state wouldn't be overlooked).

Thank you.

Steven J Gold wrote:Deduplication (and therefore, QRecall) should be my friend, so I've jumped onto the Beta hoping to become a user.

Welcome aboard! Now we'll see if we can get you to stay.

But QRecall pales in comparison to TimeMachine in one important aspect: Impact of QRecall on system usability.

I rarely notice when Time Machine is doing it's hourly stuff,, but QRecall severely impacts my computer. Suddenly, my Mac's operations like web browsing, file manipulation -- anything which requires disk access -- slow down and I wonder "What the heck's going on?" and the answer is QRecall. Especially for operations like compacting an archive or verifying.

I freely admit that the CPU and memory requirements involved in comparing every block of file data to a corpus of potentially millions of previously captured blocks, calculating checksums, generating error detection and correction codes, compression, and other tasks are vast compared to that of simply copying data from one drive to another. Keeping QRecall from interfering with your other work, therefore, can be a challenge.

(1) Time Machine sets the "use low-priority I/O" flag which gives precedence to non-Time Machine I/O, thereby lessening the impact of a backup. Could this be made a settable option in QRecall?

QRecall already does this. But, again, QRecall is doing orders of magnitude more work than Time Machine, so it still takes a toll on performance.

(2) There are times I *really* need all the performance I can get from my Mac (like when running Windows in a virtualized environment) and many of QRecall's operations take *hours* to complete. I've learned the hard way quitting QRecall in the mist of a long operation (like a compact) may have dire consequences!

I sure hope there are no dire consequences! (Unless you're force quitting a merge or compact action, in which case there can be dire consequences.) If you need to stop an action, use the stop button in the monitor window or send the QRecallHelper process a quit (TERM) signal, and not a force quit (KILL) signal. The stop or TERM signal will tell QRecall to find a break in its work, gracefully stop, and close the archive.

Could we *please* have a "Pause" button? Something which would pause QRecall until a "Resume" button is pressed?

In the QRecall Monitor window, there's a little stop (X) button in the upper right corner of each action progress pane. Click-and-hold (or Control+click) that button and you'll get a pop-up menu. In that menu you'll find two sets of commands of interest.

First is the Pause For > submenu. You can select to pause (suspend) the action for a brief time period between 5 minutes and 4 hours. Once you've paused an action, the menu item changes into a Resume command that will end the pause mode immediately.

There are also Stop and Stop and Reschedule commands. The first simply stops (quits, TERM signals) the process, identical to simply clicking the stop button. The second stops the action, but prompts you to immediately set a time at which the action is restarted. (This command only applies to actions started via an action document, because only actions can be scheduled.)

And here are some other tips:

In the QRecall Monitor menu (or in the QRecall application's Action menu, if you're not using the monitor menu), you'll find a Hold all Schedules > submenu that will suspend all of the scheduled actions for a period of time. This command affects action that are scheduled to run but haven't started yet, while the Pause for > commands suspend an already running action.

Time consuming actions can be scheduled to run late at night or early in the morning. You can add power requests to the schedule so that the computer starts up when the action is about to run and/or shuts down or goes to sleep when it's finished.

The really time consuming actions, like Compact, don't have to be run very frequently. Compact really doesn't need to be run more than once a month. How often you run merge actions is a matter of taste, but these too can be deferred for days or weeks with no significant impact on your archive. In fact, merge is more efficient if run less frequently. The other big time consumer is verify, but that can be paused or stopped without any consequences.

If you have a really large (more than 2 TB) archive, the new "Defer Data De-duplication" feature added in QRecall 2.0 is there to address the performance issues of capturing data to a large archive by putting off the de-duplication work until you compact the archive. This is because the effort required to de-duplicate data grows exponentially as the archive gets bigger. By deferring de-duplication, you can capture data all week long very quickly, and then de-duplicate it en masse over the weekend.

And if you want to get really tricky, there are new application-based conditions you can add to action schedules. For example, you could ignore (not run) actions whenever your Windows emulation application was running. It's also not a good idea to try and capture virtual machine images while they are in use. Instead, you can create an event schedule to capture these after your Windows emulation application quits.

Let us know if this helps and if you have any other questions or suggestions.