Hi guys, I am reading from there for Hadoop handles file system upgrade ( http://www.storageconference.org/2010/Papers/MSST/Shvachko.pdf), it is mentioned, "and block modifications during appends use the copy on write technique",
- I think it means old and new file system will keep only one copy using hard link to save space as long as the file has no change, and if during upgrade, the file changed (during append operation), then a new updated file will be created in order to save space. I am not sure if my understanding is correct? - Another question is, copy-on-write only used to save space for keeping snapshot information during file system upgrade? Or it has more broad use cases in HDFS? regards, Lin
