I've been using JFS on Linux Debian distributions since Lenny, currently using Jessie, and it's always worked well for me, however I've never worked with files over 1TB in size until a few days ago.
Using gddrescue I created a 2TB disk image file from a good 2TB drive onto a good 4TB drive, the performance at the start was as expected, however once it reached about 1TB the performance dropped from about 100-120Mb/s down to 3-5Mb/s. When using gddrescue to copy the image file to another 4TB disk, it again dropped to a crawl after reaching the mid-way point at 1TB. Using gddrescue I could reverse direction of the transfer, and that would speed things up to about 20-10MB/s but it would again slow to a crawl as it approached the mid-way point at 1TB. I also tried using rsync to copy the image file, but got the same results, so the problem was not due to gddrescure. I tried two separate 4TB disks and got the same results. Both disks (4TB WD "green") are brand new and I've never had problems with these disks before, and SMART status is all OK. I can copy a 500GB disk image, made using the exact same process as the 2TB image, between disks no problem, so it appears to be related to the size exceeding 1TB. When extracting the file system from the 2TB disk image, the same behavior is seen, at about the 1TB point, the file extraction process quickly slows down 10x and reaches a low point of about 3Mb/s, it begins to gradually speed up after the midway point but never reaches full speed again (I get only 10-20Mb/s). After file system extraction completes (many hours later), the complete 2TB file structure can be transfered at expected speeds between disks. The performance problem only happens when working with the 2TB disk image file. Has anyone else seen this behavior when working with JFS and >1TB sized files? ------------------------------------------------------------------------------ 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
