Even before Jim Dalrymple
complained about iTunes tag modification,
MacNN was
testing corruption and alteration of user music libraries under the iTunes Music library matching service. With another iTunes update comes another round of testing to see if the problem has finally been completely dealt with. After analysis over the last eight days, we're pleased to report that the corruption issues seem to be
mostly fixed, but unfortunately Apple's fixes fall just a hair-breadth short of utter resolution.
Test equipment
Our test platforms are a trio of 2013 Mac mini computers on the newest version of OS X and iTunes. Network library stores are gleaned from a Drobo 5D, Synology RackStation RS 214, Lenovo Iomega IS2, and a Rosewill RSV-S8 NAS device. The iTunes host machine is a 2013 i7 Mac mini, running OS X 10.10.5. For a control, we have a 2010 Mac Mini running OS X 10.10.5 and iTunes 12.1.2, as well as a very old 2007 Mac Mini on OS X 10.7.5 running iTunes 11.4. As a reminder, having libraries stores elsewhere than the user's home folder is trivial to do without symbolic links or other file system trickery, and remains a supported feature for iTunes.
We re-ripped all of the music for the last round of testing, so there was no need to do so this time. The library weighs in at 400GB, with around 120,000 discrete tracks. Adequate bandwidth for connection was available with a FiOS connection, with 150/75 Mbit speeds. The issue with a non-Apple Music subscriber suffering from altered tags was rectified in the last iTunes update, and was not tested in this round.
Methodology
Individual drives and network shares were connected one-by-one to one of the newer Mac minis being used as our primary test rig. Each configuration was allotted 10 hours allotted for continuous iTunes and network access, with both computers and drives prevented from sleeping. The testing process running near continuously for eight days allowed for 18 configurations to be tested over that time. Over the entire test period, two USB 3.0 enclosures had one file modified each, while on the test rig, and the Rosewill NAS together had only one. An internal library was unaltered, as expected.
Two of the newer Mac minis were used for continuous service testing for the whole eight days. One of the newer Mac minis attached to a Drobo 5D had two tags changed, and one Mac mini with an external USB 3.0 drive hosting the library had no changes over that time span. In parallel, zero files were modified on the control iTunes 11.4 installation, nor were any changed on the iTunes 12.1.2 library over the entire eight-day run. Both control libraries were hosted on external USB drives.
The pair of newer machines connected to the Drobo and external library respectively will continue to run until the next round of iTunes updates, and we'll report back if things suddenly implode. When the next major point release of iTunes arrives, either 13.0 or 12.4, we'll break out the entire array of test equipment, and do it all again.
Conclusions
Is the minor alteration acceptable? That depends on the user's listening habits, we suspect. In all of the modified files, the track's album association was changed with attendant track number and cover art alteration, but other details were untouched. For track-centric listeners, this isn't an issue. With album-oriented music purveyors, this is still a problem, but far better than it was when iTunes Music launched.
We've tested a lot of configurations, but we can't possibly test them all. Given that we still had a track or two here and there change, we suspect that problems may still crop up with some users every so often. Our overall recommendation remains the same: make sure you've got your iTunes library laden with CD-ripped music backed up in its entirety if you wish it to remain utterly pristine. Copying the entire iTunes folder to a backup location retains track play counts and playlists when reloaded into iTunes, so this is our backup method of choice.
We're pleased that the issue seems mostly resolved. However, in the rush to roll out Apple Music on time, we think that the cloud-based music matching functionality changes from the original iTunes Match happened haphazardly, to the detriment of users. We'll see if the next major revision brings perfection. With any luck, that will be the last battery of testing we'll need on the iTunes library alteration issue.
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