Trouble configuring YaCy in Linux

Alexios · February 3, 2026, 12:51pm

I’m looking forward to being able to thoroughly utilize YaCy; however, I keep running into issues. 2 days ago, I installed it (via Linux) for the first time, and it worked fine for a day before being unable to connect to localhost. After trying unsuccessfully to troubleshoot it, I uninstalled it and attempted to install it via Docker. Again, it worked fine- this time for a couple of hours- before I encountered the same issue: “localhost can’t be reached”… “connection refused”. So, I uninstalled it via Docker and attempted a reinstall via Linux, though nothing is working. From then to now, I’ve attempted every legitimate “quick fix” to make YaCy work- checking ports (in use/listening), making sure Apache2 is running, checking my network and firewall, flushing browser and DNS cache, router settings, browser settings, and different browsers- but nothing is working. I would appreciate any help that other users could offer so that I can fully be a part of this project.

For the record, through all of this (YaCy working and not), I’m using Linux Mint 22.3 - Cinnamon 64-bit, Brave and Mullvad browsers, and all software is fully updated.

roamn · February 4, 2026, 2:56am

Welcome

Have you increased the default memory of 600 mb?
I recommend 1500mb to start with.

http://localhost:8090/Performance_p.html

Alexios · February 4, 2026, 2:47pm

Thank you very much for your reply, roamn. While it was loading/working, yes, I did increase the default memory when it became an issue; however, the problem now is that, no matter how I attempt to troubleshoot the problem, I can no longer get into localhost at all.

roamn · February 5, 2026, 3:11am

What Java version are you running? (java -version)

If possible, could you share the last ~40 lines of DATA/LOG/yacy00.log

Alexios · February 5, 2026, 9:45pm

I’m running Java 17.0.18 (openjdk)

…and here are the last ~40 lines:

I 2026/02/03 04:55:01 HeapReader * using a dump of the index of /home/alex/yacy/DATA/INDEX/freeworld/SEGMENTS/default/text.index.20260201092455498.blob.
I 2026/02/03 04:55:01 HeapReader * saturation of text.index.20260201193521407.blob.8ERXpwkoHfdH.idx: keylength = 4, vallength = 3, size = 36731, maximum saving for index-compression = 0 MB, exact saving for value-compression = 0 MB
I 2026/02/03 04:55:01 HeapReader * using a dump of the index of /home/alex/yacy/DATA/INDEX/freeworld/SEGMENTS/default/text.index.20260201193521407.blob.
I 2026/02/03 04:55:01 HeapReader * saturation of text.index.20260201211548139.blob.tFzjwZR9O_vq.idx: keylength = 5, vallength = 3, size = 34328, maximum saving for index-compression = 0 MB, exact saving for value-compression = 0 MB
I 2026/02/03 04:55:01 HeapReader * using a dump of the index of /home/alex/yacy/DATA/INDEX/freeworld/SEGMENTS/default/text.index.20260201211548139.blob.
I 2026/02/03 04:55:02 HeapReader * saturation of text.index.20260201225416171.blob.5lvoyKl0z28T.idx: keylength = 6, vallength = 4, size = 577437, maximum saving for index-compression = 3 MB, exact saving for value-compression = 2 MB
I 2026/02/03 04:55:02 HeapReader * using a dump of the index of /home/alex/yacy/DATA/INDEX/freeworld/SEGMENTS/default/text.index.20260201225416171.blob.
I 2026/02/03 04:55:02 HeapReader * saturation of text.index.20260201083227076.blob.46vTMWa4AjF6.idx: keylength = 5, vallength = 3, size = 23169, maximum saving for index-compression = 0 MB, exact saving for value-compression = 0 MB
I 2026/02/03 04:55:02 HeapReader * using a dump of the index of /home/alex/yacy/DATA/INDEX/freeworld/SEGMENTS/default/text.index.20260201083227076.blob.
I 2026/02/03 04:55:02 HeapReader * saturation of text.index.20260201165004244.blob.Al27acaQHr7X.idx: keylength = 5, vallength = 3, size = 45327, maximum saving for index-compression = 0 MB, exact saving for value-compression = 0 MB
I 2026/02/03 04:55:02 HeapReader * using a dump of the index of /home/alex/yacy/DATA/INDEX/freeworld/SEGMENTS/default/text.index.20260201165004244.blob.
I 2026/02/03 04:55:03 HeapReader * saturation of text.index.20260201151900048.blob.uBPcCMNGnULB.idx: keylength = 5, vallength = 3, size = 62092, maximum saving for index-compression = 0 MB, exact saving for value-compression = 0 MB
I 2026/02/03 04:55:03 HeapReader * using a dump of the index of /home/alex/yacy/DATA/INDEX/freeworld/SEGMENTS/default/text.index.20260201151900048.blob.
I 2026/02/03 04:55:03 HeapReader * saturation of text.index.20260201193217839.blob.icXmhVK_afhT.idx: keylength = 5, vallength = 3, size = 29817, maximum saving for index-compression = 0 MB, exact saving for value-compression = 0 MB
I 2026/02/03 04:55:03 HeapReader * using a dump of the index of /home/alex/yacy/DATA/INDEX/freeworld/SEGMENTS/default/text.index.20260201193217839.blob.
I 2026/02/03 04:55:03 HeapReader * saturation of text.index.20260201092358413.blob.Bzv6ge6VD5jH.idx: keylength = 5, vallength = 3, size = 57106, maximum saving for index-compression = 0 MB, exact saving for value-compression = 0 MB
I 2026/02/03 04:55:03 HeapReader * using a dump of the index of /home/alex/yacy/DATA/INDEX/freeworld/SEGMENTS/default/text.index.20260201092358413.blob.
I 2026/02/03 04:55:03 HeapReader * saturation of text.index.20260201111257528.blob.wy-uZcCbV0Ul.idx: keylength = 5, vallength = 3, size = 57373, maximum saving for index-compression = 0 MB, exact saving for value-compression = 0 MB
I 2026/02/03 04:55:03 HeapReader * using a dump of the index of /home/alex/yacy/DATA/INDEX/freeworld/SEGMENTS/default/text.index.20260201111257528.blob.
I 2026/02/03 04:55:03 HeapReader * saturation of text.index.20260201000215241.blob.Iu3myOjzomoe.idx: keylength = 5, vallength = 3, size = 33983, maximum saving for index-compression = 0 MB, exact saving for value-compression = 0 MB
I 2026/02/03 04:55:03 HeapReader * using a dump of the index of /home/alex/yacy/DATA/INDEX/freeworld/SEGMENTS/default/text.index.20260201000215241.blob.
I 2026/02/03 04:55:03 HeapReader * saturation of text.index.20260201223537799.blob.Mb-WfITixbvz.idx: keylength = 5, vallength = 3, size = 34934, maximum saving for index-compression = 0 MB, exact saving for value-compression = 0 MB
I 2026/02/03 04:55:03 HeapReader * using a dump of the index of /home/alex/yacy/DATA/INDEX/freeworld/SEGMENTS/default/text.index.20260201223537799.blob.
I 2026/02/03 04:55:03 HeapReader * saturation of text.index.20260201213315023.blob.cAxhrDfkn3dN.idx: keylength = 5, vallength = 3, size = 27826, maximum saving for index-compression = 0 MB, exact saving for value-compression = 0 MB
I 2026/02/03 04:55:03 HeapReader * using a dump of the index of /home/alex/yacy/DATA/INDEX/freeworld/SEGMENTS/default/text.index.20260201213315023.blob.
I 2026/02/03 04:55:03 HeapReader * saturation of text.index.20260201085559584.blob.tRI2o4qyS4DO.idx: keylength = 4, vallength = 3, size = 41816, maximum saving for index-compression = 0 MB, exact saving for value-compression = 0 MB
I 2026/02/03 04:55:03 HeapReader * using a dump of the index of /home/alex/yacy/DATA/INDEX/freeworld/SEGMENTS/default/text.index.20260201085559584.blob.
I 2026/02/03 04:55:03 HeapReader * saturation of text.index.20260201213527430.blob.N5nyBiOCHGss.idx: keylength = 5, vallength = 3, size = 55088, maximum saving for index-compression = 0 MB, exact saving for value-compression = 0 MB
I 2026/02/03 04:55:03 HeapReader * using a dump of the index of /home/alex/yacy/DATA/INDEX/freeworld/SEGMENTS/default/text.index.20260201213527430.blob.
I 2026/02/03 04:55:04 HeapReader * saturation of text.index.20260201211936640.blob.VRyltUmG75aN.idx: keylength = 5, vallength = 4, size = 332096, maximum saving for index-compression = 1 MB, exact saving for value-compression = 1 MB
I 2026/02/03 04:55:04 HeapReader * using a dump of the index of /home/alex/yacy/DATA/INDEX/freeworld/SEGMENTS/default/text.index.20260201211936640.blob.
I 2026/02/03 04:55:04 HeapReader * saturation of text.index.20260201152249277.blob.wWL4m91OzEfR.idx: keylength = 5, vallength = 3, size = 30499, maximum saving for index-compression = 0 MB, exact saving for value-compression = 0 MB
I 2026/02/03 04:55:04 HeapReader * using a dump of the index of /home/alex/yacy/DATA/INDEX/freeworld/SEGMENTS/default/text.index.20260201152249277.blob.
W 2026/02/03 04:55:05 ConcurrentLog * net.yacy.cora.util.SpaceExceededException: 2451840 bytes needed for RowCollection grow after OutOfMemoryError Java heap space: 38373200 free at Tue Feb 03 04:55:05 EST 2026
net.yacy.cora.util.SpaceExceededException: 2451840 bytes needed for RowCollection grow after OutOfMemoryError Java heap space: 38373200 free at Tue Feb 03 04:55:05 EST 2026
at net.yacy.kelondro.index.RowCollection.ensureSize(RowCollection.java:276)
at net.yacy.kelondro.index.RowCollection.addUnique(RowCollection.java:425)
at net.yacy.kelondro.index.RowCollection.addUnique(RowCollection.java:403)
at net.yacy.kelondro.index.RAMIndex.addUnique(RAMIndex.java:216)
at net.yacy.kelondro.index.RAMIndexCluster.addUnique(RAMIndexCluster.java:133)
at net.yacy.kelondro.index.RowHandleMap.(RowHandleMap.java:114)
at net.yacy.kelondro.blob.HeapReader.initIndexReadDump(HeapReader.java:179)
at net.yacy.kelondro.blob.HeapReader.(HeapReader.java:91)
at net.yacy.kelondro.blob.HeapModifier.(HeapModifier.java:58)
at net.yacy.kelondro.blob.ArrayStack.(ArrayStack.java:209)
at net.yacy.kelondro.rwi.ReferenceContainerArray.(ReferenceContainerArray.java:68)
at net.yacy.kelondro.rwi.IndexCell.(IndexCell.java:99)
at net.yacy.search.index.Segment.connectRWI(Segment.java:162)
at net.yacy.search.Switchboard.(Switchboard.java:578)
at net.yacy.yacy.startup(yacy.java:215)
at net.yacy.yacy.main(yacy.java:832)
I 2026/02/03 04:55:05 HeapReader * generating index for /home/alex/yacy/DATA/INDEX/freeworld/SEGMENTS/default/text.index.20260201224925650.blob, 117 MB. Please wait.
I 2026/02/03 04:55:06 ConcurrentLog shutdown of ConcurrentLog.Worker void because it was not running.
E 2026/02/03 04:55:06 UNCAUGHT-EXCEPTION * Thread main: Java heap space
java.lang.OutOfMemoryError: Java heap space

java.lang.OutOfMemoryError: Java heap space
E 2026/02/03 04:55:06 ConcurrentLog Java heap space
java.lang.OutOfMemoryError: Java heap space

My apologies for the delay in replying to you, and thank you very much for any help that you can offer.

roamn · February 6, 2026, 1:12am

What is your total system memory size?

What is the approx age of peer?

Can you remember the approx number of Documents in index?

Alexios · February 6, 2026, 8:00pm

Total system memory size is: 24GB Ram, 500GB SSD

Approx age of peer: It was less than 2 days for the first Linux installation, and less than a day for the Docker installation. Since then, as mentioned before for the current Linux install, localhost refuses to connect.

Approx number of Docs in index: Other than crawling one review website, I was going through Project Gutenberg- I think the last count for the first Linux install was over 400K.

roamn · February 7, 2026, 9:55am

Try this
What to delete (safe)

Stop YaCy first, then:

cd /home/alex/yacy/DATA/INDEX/freeworld/SEGMENTS/default
rm -f text.index.*.blob*

This removes only:

Corrupted / oversized text index blobs
Rebuilt automatically on next start

What NOT to delete

Do not delete these:

collection.*
citation.*
webgraph.*
hosts.*

Those are your core indexes.

Alexios · February 7, 2026, 10:29pm

First, thank you again for your help. I did as suggested and included a full system restart; unfortunately, I’m still getting the same message (and blank screen):

localhost refused to connect.

ERR_CONNECTION_REFUSED

roamn · February 7, 2026, 10:44pm

While YaCy is starting, check the log:

tail -f /home/alex/yacy/DATA/LOG/yacy00.log

If you see messages like:

HeapReader * generating index for text.index....

then YaCy is working and rebuilding — even if localhost:8090 still refuses for a bit.
If you still see OutOfMemoryError in the log, the heap is still too small.