How to fix the Spotlight disk write issues?

[kharys415]

I haven't seen this mentioned in a while, making it look like it disappeared, but it never did for me even on 15.7.4 beta. Whenever I turn on Spotlight indexing, the mds_stores process constantly writes to the SSD in sleep mode, reaching over 1TB in several days.

I've tried cleaning out its index with Onyx, with terminal commands manually (also deleting .Spotlight-V100 folders), disabling iCloud sync (some people mentioned it being a trigger for the bug), no luck. Is there anything I could do to diagnose and solve it? I imagine it's having a fit about some of my files or apps. The system was reinstalled once (don't remember if the issue was present in the previous installation) and I backed up and moved all my personal files and some app data (manually, without using TM or anything), so I don't think another reinstall will help it unless I get rid of all that.

 

[Fishrrman]

Since Spotlight was first introduced years ago, I didn't like the idea of constant indexing of my drives.

So... I took the easy way out -- I DISABLED spotlight, and have not used it since.
I simply don't need it.

For searching, I much prefer using either "EasyFind" or "Find Any File" -- both of which are small and free.

You can disable spotlight using the terminal.
Also, if you put a small text file on each drive named:
.metadata_never_index

...then spotlight will ignore that volume and never index it.
IMPORTANT:
You will note the period at the beginning of the file name, which makes it invisible.
You can toggle invisible items in the finder to make them viewable with the key combination of "command-shift-period"...

 

[kharys415]

I'm aware I could disable it and I've had it like that for a while now, but I'm ok with doing some tinkering and I'd still prefer to actually find the issue and fix it as it's a core OS feature that isn't supposed to be messing with SSDs. My old Macs don't do anything like that.

Trying out a new approach, blacklisting everything iCloud-related with the Search Privacy setting (Photo Library, TV, Apple Music) and folders with the largest amounts of files modified most often (using HoudahSpot to find them). For the latter, Biome and DuetExpertCenter folders in ~/Library were the worst offenders. Couldn't yet find out what exactly Biome and DuetExpertCenter are, but mds_stores disk writes went down by a whole lot, from ~100GB to just ~1GB overnight.

Will try gradually allowing the folders back over time and report here if I find the true culprit.

 

[gilby101]

This doesn't help with your core problem, but some background.

Couldn't yet find out what exactly Biome and DuetExpertCenter

Biome is for improving Spotlight/Siri results by keeping information about what you Mac is doing (i.e. your activity) - analogy with "gut biome". Though uncommon, I have read of cases where the folder has got very large. It is safe to delete the folder, reboot and let the system recreate it (hopefully smaller than before). It is excluded from Time Machine backup. It doesn't contain anything for Spotlight to index, so excluding from Spotlight index seems pointless.

DuetExpertCentre is for synchronisation with other devices.

Both of these have high background activity. This is expected.

Whenever I turn on Spotlight indexing, the mds_stores process constantly writes to the SSD in sleep mode, reaching over 1TB in several days.

You are asking Spotlight to recreate your file system indexes. So you must expect lots of activity whilst they are being rebuilt (though 1TB does seem excessive!). Let it settle down. My mds_stores process has written 900 MB in the last 24 hours (Intel macOS 15.7.3).

As a general comment, once you start down the path of excluding random stuff from Spotlight indexing and rebuilding its indexes you are likely to get deeper into the mire. When I have rebuilt indexes this has always been with mdutil commands - not GUI apps (like Onyx) which hide what is really being done.

 

[kharys415]

What motivated me to try the exclusion method was someone's guess that it's folders with extreme amounts of files making it freak out, seen here. Except I deleted the V100 folders from all the partitions with sudo mdutil -X commands without booting into recovery, and did the exclusions based on the amounts of files and how often they were modified, not the folder sizes. From what I'm seeing now, it does manage to bring it down to reasonable write amounts. Tried running these mdutil commands without the exclusions before, as already mentioned, but it didn't work.

Doesn't explain why did this become a thing with Sequoia specifically though, its biggest addition after Sonoma is Apple Intelligence which I never even turned on and folders with large amounts of files (as well as cloud sync) were a thing in older systems too.

I'm 99% sure it's not intended software behavior I'm dealing with here, as this bug attracted some attention back when Sequoia first released (mentioned in a Reddit bug megathread, a couple threads here, other sources). I actually didn't mess with Spotlight at all before noticing it (which I did while investigating a surprisingly large number of total SSD writes for how long I owned the Mac and the workloads I generally did on it), at the very least it had a couple months to index my system, plenty for a 256GB SSD that I don't even fill up past 70%.

 

[kharys415]

Well, everything non-destructive I did so far (exclusions, index removals and rebuilds, Spotlight preference resets etc) was seemingly not the way. These Library folders didn't matter, as for cloud-related folders - excluding them definitely lowered the writes but the problem was still there, and allowing them back brought it back to 100gb+ daily. I initially thought the problem was solved because I kept it off the charger at the time, and it turns out it mds_stores only does this thing when Mac is both sleeping and charging. I also attempted reinstalling from recovery (without erasing anything) and it started writing even more after doing that. Noticed mediaanalysisd had high writes at times and was throwing some errors in logs too, so I deleted and rebuilt my Photo library - still no luck.

In the end I fixed the issue, but I don't know how exactly. Failed to track down the true cause (fs_usage commands and logs for mds_stores didn't provide any meaningful info other than the fact it keeps doing something in the filesystem in sleep) so I just went with the nuclear option instead (full Mac erase and OS reinstall). I also wiped my iCloud Drive entirely before reinstalling, it was surprisingly difficult (some folders took many tries to actually delete) so maybe something in there was corrupted. Haven't even seen mds_stores in Activity Monitor for a while now.