en:blog:2018:2018-03-20

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en:blog:2018:2018-03-20 [2019-08-26 17:20]
Decomo 作成 		en:blog:2018:2018-03-20 [2022-01-04 09:42] (current)
Decomo
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-====== Finally understood the reason why Samba 4.7.4 wastes huge memories on NAS4Free 11.1.0.4 ======+====== Finally understood the reason why Samba 4.7.4 wastes huge RAM on NAS4Free 11.1.0.4 ======
  
 I experienced the Samba daemons wolfed a lot of memories when I looked into bad behaviour of CIFS shareing on my friend's NAS. They wastesd gigabyte order memories per one process, then consumed 16GB of physical memory and 64GB of swap. I had no choice but to shut down the machine forcibly. It was clearly unusual. I think the lack of memory caused proximately the problem because ARC couldn't use enough memory and therefore storage performance was poor. I experienced the Samba daemons wolfed a lot of memories when I looked into bad behaviour of CIFS shareing on my friend's NAS. They wastesd gigabyte order memories per one process, then consumed 16GB of physical memory and 64GB of swap. I had no choice but to shut down the machine forcibly. It was clearly unusual. I think the lack of memory caused proximately the problem because ARC couldn't use enough memory and therefore storage performance was poor.
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 I tried to fiddle with some options, then it seemed a shadow copy option brought the disaster. A following picture shows difference between the option 'On' and 'Off' of ''top'' command. I tried to fiddle with some options, then it seemed a shadow copy option brought the disaster. A following picture shows difference between the option 'On' and 'Off' of ''top'' command.
  
 +<WRAP centeralign>
 {{ :blog:2018:samba_memory_usage_comparison_whether_shadow_copy_enabled.png |}} {{ :blog:2018:samba_memory_usage_comparison_whether_shadow_copy_enabled.png |}}
 +Left-side is "Shadow copy enabled", right-side is "disabled."
 +</WRAP>
 +
  
 It is alarmingly at-a-glance. The memory usages were different order of magnitude literally. The samba enabled shadow copy option almost dried up the memory in less than a day, on the other hand, disabled one works fine four-day-old alghough the load average is up to 13. FYI, the file sharing service also works in this situation. It is alarmingly at-a-glance. The memory usages were different order of magnitude literally. The samba enabled shadow copy option almost dried up the memory in less than a day, on the other hand, disabled one works fine four-day-old alghough the load average is up to 13. FYI, the file sharing service also works in this situation.
  
 The VSS in Samba means a ''vfs_shadow_copy2'' module has some bugs, doesn't it? I felt there were no problem if the options was enabled when NAS4Free was version 9 or 10 although my memory was so dim. The VSS in Samba means a ''vfs_shadow_copy2'' module has some bugs, doesn't it? I felt there were no problem if the options was enabled when NAS4Free was version 9 or 10 although my memory was so dim.
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  • by Decomo