What is a Zpool scrub?

What is a Zpool scrub?

DESCRIPTION. zpool scrub [ -s | -p ] [ -w ] pool Begins a scrub or resumes a paused scrub. The scrub examines all data in the specified pools to verify that it checksums correctly. For replicated (mirror or raidz) devices, ZFS automatically repairs any damage discovered during the scrub.

How long is Zpool scrub?

A ZFSSA with 192 4TB drives, configured as a single RAIDz1 pool, with only 1TB of data currently in it, finished a disk scrub in less than 90 seconds.

What does disk scrubbing mean?

Disk scrubbing is a background process that reads disks during idle periods to detect irremediable read er- rors in infrequently accessed sectors. Timely detection of such latent sector errors (LSEs) is important to reduce data loss.

How often should you scrub Freenas?

SCRUBS: Every 1st and 15th of the month at 4 am. The threshold on 10 days. Short S.M.A.R.T tests: Every 5th, 12th, 19th and 26th of the month at 3 am. Long S.M.A.R.T tests: Every 8th and 22nd at 4 am.

How do I clear Zpool errors?

Type zpool clear raid2 to clear the errors and initiate a scrub.

How do I check my Zpool status?

How to check zpool status in Solaris

1. Basic Storage Pool Health Status. The simplest way to request a quick overview of pool health status by zpool status -x command. Example:
2. Detailed Health Status. You can request a more detailed health summary by using the -v option to see if pool state is ONLINE.

What does scrub the data mean?

Data scrubbing, also referred to as data cleansing, is the process of amending or removing data in a database that is incorrect, incomplete, improperly formatted or duplicated. Using a data scrubbing tool can save a database administrator a significant amount of time and can be less costly than fixing errors manually.

What is scrubbing Freenas?

What are Scrubs. Scrubs on a ZFS Volume helps you to identify data integrity problems, detects silent data corruptions and provides you with early alerts to disk failures. It also cleans up your disks. Scrubs only checks used disk space, that’s why we also use SMART tests, to check the whole disk health.

How often should I scrub my ZFS pool?

It’s generally a good idea to scrub consumer-grade drives once a week, and enterprise-grade drives once a month. How long the scrub takes depends on how much data is in your pool; ZFS only scrubs sectors where data is present so if your pool is mostly empty it will be finished fairly quickly.

How to use the scrub feature in ZFS?

Well, there is a solution. ZFS provides a scrub option to read back all of the data in the file system and validate that the data still matches the computed checksum. This feature can be access by running the zpool utility with the “scrub” option and the name of the pool to scrub:

How to check scrub status in zpool utility?

To view the status of the scrub you can run the zpool utility with the “status” option: The scrub operation will consume any and all I/O resources on the system ( there are supposed to be throttles in place, but I’ve yet to see them work effectively ), so you definitely want to run it when you’re system isn’t busy servicing your customers.

How to see how much space is consumed by a ZFS pool?

Using ZFS Volumes – When a ZFS file system is created and pool space is consumed, you can view the file system space consumption by using the zpool list command. For example: If you create a 10GB ZFS volume, the space is not accounted for in the zpool list command.