Monitoring ZFS on Linux with ZED

ZFS on Linux is without a doubt one of the most robust and powerful file systems available today.

However, despite its high reliability, unexpected problems can occur quickly, especially with the underlying hardware. It is important that any error is immediately noticed and reported to the responsible system administrator, who can then intervene in time to prevent worse.

ZFS has and “Event Daemon” (ZED) that monitors all ZFS events (such as a scrub being completed) and sends an alert email when an event occurs. It is included with ZFS and can be installed as follows:

# apt install zfs-zed

# vi /etc/zfs/zed.d/zed.rc

##
# zed.rc
#
# This file should be owned by root and permissioned 0600.
##

##
# Absolute path to the debug output file.
#
#ZED_DEBUG_LOG="/tmp/zed.debug.log"

##
# Email address of the zpool administrator for receipt of notifications;
#   multiple addresses can be specified if they are delimited by whitespace.
# Email will only be sent if ZED_EMAIL_ADDR is defined.
# Disabled by default; uncomment to enable.
#
ZED_EMAIL_ADDR="you@yourdomain.com"

##
# Name or path of executable responsible for sending notifications via email;
#   the mail program must be capable of reading a message body from stdin.
# Email will only be sent if ZED_EMAIL_ADDR is defined.
#
ZED_EMAIL_PROG="mail"

##
# Command-line options for ZED_EMAIL_PROG.
# The string @ADDRESS@ will be replaced with the recipient email address(es).
# The string @SUBJECT@ will be replaced with the notification subject;
#   this should be protected with quotes to prevent word-splitting.
# Email will only be sent if ZED_EMAIL_ADDR is defined.
#
ZED_EMAIL_OPTS="-s '@SUBJECT@' @ADDRESS@"

##
# Default directory for zed lock files.
#
ZED_LOCKDIR="/var/lock"

##
# Minimum number of seconds between notifications for a similar event.
#
ZED_NOTIFY_INTERVAL_SECS=3600

##
# Notification verbosity.
#   If set to 0, suppress notification if the pool is healthy.
#   If set to 1, send notification regardless of pool health.
#
ZED_NOTIFY_VERBOSE=1

##
# Send notifications for 'ereport.fs.zfs.data' events.
# Disabled by default
#
#ZED_NOTIFY_DATA=1

##
# Pushbullet access token.
# This grants full access to your account -- protect it accordingly!
#   <https://www.pushbullet.com/get-started>
#   <https://www.pushbullet.com/account>
# Disabled by default; uncomment to enable.
#
#ZED_PUSHBULLET_ACCESS_TOKEN=""

##
# Pushbullet channel tag for push notification feeds that can be subscribed to.
#   <https://www.pushbullet.com/my-channel>
# If not defined, push notifications will instead be sent to all devices
#   associated with the account specified by the access token.
# Disabled by default; uncomment to enable.
#
#ZED_PUSHBULLET_CHANNEL_TAG=""

##
# Default directory for zed state files.
#
#ZED_RUNDIR="/var/run"

##
# Turn on/off enclosure LEDs when drives get DEGRADED/FAULTED.  This works for
# device mapper and multipath devices as well.  Your enclosure must be
# supported by the Linux SES driver for this to work.
#
ZED_USE_ENCLOSURE_LEDS=1


##
# The syslog priority (e.g., specified as a "facility.level" pair).
#
ZED_SYSLOG_PRIORITY="daemon.notice"

##
# The syslog tag for marking zed events.
#
ZED_SYSLOG_TAG="zed"

Next run a scrub to test our settings.

# zpool scrub my-pool