Question-57: Select correct statements regarding Disk Mount options for the host on Cloudera Private Cloud Base?

1. All drives used by DataNode machines for data need to be mounted without the use of RAID Drives.
2. All drives used by DataNode machines for data need to in /etc/fstab be mounted using the noatime option
3. All drives used by DataNode machines for data need to in /etc/fstab be mounted without using the noatime option
4. In case of SSD or flash turn on TRIM by specifying the discard option when mounting, this reduces premature SSD wear and device failures, while primarily avoiding long garbage collection pauses.  

Answer:

Exp: Disk Mount Options: The HDFS by design is a fault-tolerant file system. All drives used by DataNode machines for data need to be mounted without the use of RAID Drives should be mounted in /etc/fstab using the noatime option (which also implies nodiratime). In case of SSD or flash turn on TRIM by specifying the discard option when mounting, this reduces premature SSD wear and device failures, while primarily avoiding long garbage collection pauses. In /etc/fstab ensure that the appropriate file systems have the noatime mount option specified:

To enable TRIM, edit /etc/fstab and set mount option discard as well.

/dev/sdb1 /data ext4 noatime,discard 0 0

Disk Mount Naming Convention: For ease of administration, it is recommended to mount all of the disks on the DataNode machines with a naming pattern, for example:

/data1

/data2

/data3

/data4

/data5

/data6