Customer informed that they are unable to gather TS logs due to a missing disk space error on Junos space.
Error message: "Not enough space to save the logs. Please expand '/var' partition."
While checking the df -h command yielded information which didnt clearly indicated missing disk space on "/var" partition.
Output of df command from all the different junos space Apps output was as below:

--- app01 ---
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/jmpvgnocf-lvvar 496G 251G 223G 54% /var
--- app02 ---
/dev/mapper/jmpvgnocf-lvvar 496G 261G 213G 56% /var
--- app03 ---
/dev/mapper/jmpvgnocf-lvvar 496G 299G 175G 64% /var
--- app04 ---
/dev/mapper/jmpvgnocf-lvvar 496G 141G 333G 30% /var
--- app05 ---
/dev/mapper/jmpvgnocf-lvvar 496G 131G 343G 28% /var
--- app06 ---
/dev/mapper/jmpvgnocf-lvvar 496G 120G 354G 26% /var
--- app07 ---
/dev/mapper/jmpvgnocf-lvvar 496G 118G 356G 25% /var
--- app08 ---
/dev/mapper/jmpvgnocf-lvvar 496G 120G 354G 26% /var

Customer observed the following error while taking the TS logs backup:

From the Jobs, you can see the completed failed job with an error:

If you expand the job failure details there you can see the error message as below:

Below are the details about the TS log files:

1. Troubleshooting log file is stored at the following location on one of the Junos Space node that completes the job: /var/cache/jboss/space-logs
2. The logical volume for this location is "/var".
3. During TS log creation, Junos Space performs a strict pre-check on /var free space, using an estimated maximum TS bundle size (often hundreds of GB in multi-node setups). As even "/var/log" is in some hundreds of GB.
4. Based on your output, even though you do have free space in "/var", the pre-check threshold requirement for a fresh TS log file is not met, so the job fails before writing any files.
5. In our customer case, increasing the size of "/var/" from 175 to 300 GB on App node 3 resolved the issue. So, Node 3's Disk space is being used for TS creation; hence, space is required on this node.
6. Junos Space calculates the required space for log files as follows:
   1. Minimum free space on /var = 2 × Total uncompressed log size
   2. The system sums up the size of all uncompressed logs it needs to collect (totalLogSize), then assumes 50% compression
   3. System checks if /var has at least half of the total uncompressed log size free. If not, it fails with the message 'Not enough space to save the logs.'
   4. The code uses a conservative 50% compression estimate, even though actual compression on text logs is typically 88% or higher.
   5. Space requirement will vary depending on the log size generated each time.

2026-05-22 : Article Created

2026-05-22 : Article Updated