Question-56: When creating ext4 filesystems for use with Hadoop data volumes, which of the following are Cloudera's correct recommendations?

1. Use one inode per 1 MB
2. Minimize the number of super block backups or sparse_super
3. Enable journaling or has_journal
4. Use b-tree indexes for directory trees or dir_index
5. Use extent-based allocations or extent

Answer:

Exp: Filesystem Creation Options: When creating ext4 filesystems for use with Hadoop data volumes, Cloudera recommends reducing the superuser block reservation from 5% to 1% for root (using the -m1 option) as well as setting the following options:

• use one inode per 1 MB (largefile)
• minimize the number of super block backups (sparse_super)
•  
• use b-tree indexes for directory trees (dir_index)
• use extent-based allocations (extent)

Creating such an ext4 filesystem might look like this:

mkfs –t ext4 –m 1 –O sparse_super,dir_index,extent,has_journal /dev/sdb1

Creating an xfs filesystem might look like this:

mkfs –t xfs /dev/sdb1

When creating xfs filesystems, no options are required.