> folder < 128KB so it should just mirror across nodes so it should be 7x correct.  Not quite.  Directories (and file metadata) are always mirrored, regardless of whether a FEC scheme is in use.  So in your example, it's mirrored by default, not because it's < 128 KiB.  Also, directories are mirrored at one level higher than the protection that's in place.  So in your example of +2d:1n, that directory will have 4 mirrors.  > file1 size is 176B so not sure why the number of stripes is grouped in a set of 2 (  /2 number )  A file that small will be *effectively* mirrored because the FEC algorithm doesn't have enough file data to actually create stripes.  So this file, in your example, will have 3 mirrors, each 176 B in size even though the protection policy on the file is +2d:1n.  > default   6+2/2 concurrency on    file1  And this is the example of what I said above.  You have a 4-node cluster and are using the default FEC protection policy of +2d:1n.  This means that OneFS can create stripes of 6+2/2, if it has the data to do so.  Your "file1" at 176 B doesn't have the necessary data, so OneFS will 3x mirror it (but doesn't change the *protection policy*).  If you were to append to the file to grow it beyond 128 KiB, OneFS would then switch from creating mirrors to creating FEC stripes.
hello,  i know there are lot of posts in community around this but its great if someone clarify this protection below based on size.   Number of Nodes:  7 protection level +2d:1n folder name: ztest  file name with in  folder : file1  folder < 128KB so it should just mirror across nodes so it should be 7x correct.  file1 size is 176B so not sure why the number of stripes is grouped in a set of 2 (  /2 number ).  increase the dir protection to higher requested protection than its contect is checked/set on cluster  isilon-prod# isi get /ifs | grep -i ztest default      4x concurrency on    ztest/  isilon-prod# ls -lah /ifs/ztest total 96 drwxr-xr-x     2 root  wheel    23B Jul 29 13:45 . drwxrwxrwx    60 root  wheel   1.7K Jul 29 13:55 .. -rw-r--r--     1 root  wheel   176B Jul 29 13:55 file1  isilon-prod# isi get /ifs/ztest/ POLICY    LEVEL PERFORMANCE COAL  FILE default      4x concurrency on    ./ default    8x/2 concurrency on    ../ default   6+2/2 concurrency on    file1
Dir/File Protection