Red Hat Bugzilla – Bug 1278391
Data Tiering:Files not getting migrated from hot to cold when the hot brick is full
Last modified: 2018-02-06 12:43:24 EST
+++ This bug was initially created as a clone of Bug #1271151 +++
Description of problem:
When a brick is full, files are not getting migrated at all.
I created a hot tier with 2x2 with each brick of 1GB size. That means effectively the hot tier is of 2GB size.
I started to create a file of 1.5GB using dd command, which was getting created on 1st brick. But as the 1GB gets filled, the new file stops to grow with below error:
dd: error writing ‘zerobyte.50’: Input/output error
dd: closing output file ‘zerobyte.50’: Input/output error
Now the file is not getting demoted at all and hence no more writes are going to the hot tier.
Similarly, if i fill the other brick too, then it essentially means that the whole hot tier is full.
In this case, no more new creates are being allowed even to the cold tier (also refer bz#1259312)
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1.create a 2x2 vol and start it
2.attach a tier of 2x2 with limited size, say each brick of 1GB.
Also turn on ctr (note in this case quota was not turned on)
3.Now create a file of 1.5GB such that it goes to one of the hot bricks
It will fail after it creates 1GB
4. Now this file doesnt get demoted at all
5.Now again create a 1.5GB file such that it goes to the other hot brick(to make hot layer full)
5. Now file doenst get demoted at all
File must get demoted once it is old and idle
--- Additional comment from nchilaka on 2015-10-13 05:39:20 EDT ---
--- Additional comment from nchilaka on 2015-10-13 06:43 EDT ---
--- Additional comment from Dan Lambright on 2015-10-29 17:01:33 EDT ---
DHT does not accept creation of files beyond the brick size. So I am not sure if we can fix the test the way it is structured, but nithya can confirm.
In practice the hot brick would be 10s or 100s of GB. A file created would be a fraction of that size. As files are created on the hot tier it would become more full, until eventually a watermarked was crossed. At that time files would be created on the cold tier.
*** Bug 1278392 has been marked as a duplicate of this bug. ***
Well when the hot tier is full 100% no space to set migration xattr then migration fails. The min free disk and water marks should guard us from this situation. This problem is also true for dht rebalance or afr self heal.
Yes, the doc field looks correct.
Thank you for your bug report.
We are no longer working on any improvements for Tier. This bug will be set to CLOSED WONTFIX to reflect this. Please reopen if the rfe is deemed critical.