On 02/11/2016 03:31 AM, alanb wrote: > Update: > > I reformatted one of the 4TB drives to XFS, and did another transfer of > the original 2TB image file from JFS to XFS. > > What is interesting, is when I copy the 2TB image file from the JFS > drive to the XFS drive, I still encountered the same slow down. It was > doing OK at 1TB, but when I next checked on it, it was thrashing and > slow at the 1.3TB mark and it persisted until completion, so the problem > point starts somewhere between 1TB and 1.3TB. I spot checked the CPU > usage and it was OK the whole time. > > My next test was extracting the file system from the image file on the > XFS drive to the free space on the same XFS drive (same partition), so > from XFS to XFS. When I last did the file system extraction, it was from > JFS to JFS, and it would slow down at around the 1TB mark (probably > between 1TB and 1.3TB), but this time it ran smoothly until completion. > I think this indicates that it is the reads from the large file are the > source of the problem. > > I have not yet tested transferring from XFS to JFS, but hope to give it > a try once I find the time. > > I think it is now very clear that JFS is the source of the problem, and > it's the reads that are not working properly starting somewhere between > 1-1.3TB.
I'm guessing that maybe at this point the block allocation might be breaking down and the later part of the file may be badly fragmented. I don't have time right now investigate. Just throwing out a theory. > > From now on, I'll be using XFS when dealing with very large files. Might be a good idea. JFS hasn't gotten much attention in the last several years. :-( Thanks, Dave ------------------------------------------------------------------------------ Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=272487151&iu=/4140 _______________________________________________ Jfs-discussion mailing list Jfs-discussion@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/jfs-discussion
