Use Bucket Size for Filesystem Stats

[foodprocessor]

Describe your changes in brief

• Add flag to allow users to choose whether StatFs will be populated by file cache or cloud storage.
• Provide StatFs storage usage statistics from cloud storage by default (should we flip this, or should the flag be in s3storage?)
• Correct StatFs math in file cache.
• Use same StatFs function in file cache regardless of platform (and use getAvailableSize() for platform-specific code).
• Change libfuse StatFs response to handle both file cache and cloud storage data.
• Change s3 call to HeadBucket to capture response and parse size (works for Lyve Cloud only).
• Create new function bucketExists() to replace old headBucket wrapper.

What type of Pull Request is this? (check all applicable)

• Refactor
• Feature
• Bug Fix
• Optimization
• Documentation Update

Checklist

• Tested locally
• Added new dependencies
• Updated documentation
• Added tests

Related Issues

• Related Issue #
• Closes #

[jfantinhardesty]

Great fix for the size of the bucket. On question, is there a performance concern with how often the OS may call statfs. Seems like it might be a bit slow to respond each time and was wondering if this has caused a problem with Network Optix or if you see a problem with the additional latency? Also it appears that the test TestStatFs is failing on both Linux and Windows.

[foodprocessor]

Great fix for the size of the bucket. On question, is there a performance concern with how often the OS may call statfs. Seems like it might be a bit slow to respond each time and was wondering if this has caused a problem with Network Optix or if you see a problem with the additional latency? Also it appears that the test TestStatFs is failing on both Linux and Windows.

I have tested this on both platforms. I have not seen performance issues (cloud responds in less than 100ms), and the OS seems to only call StatFs at the expected times (when viewing the mount properties and when an application calls StatFs explicitly).

[jfantinhardesty]

Looks good! I like the config option in s3storage.