Understanding ZFS Snapshots - why will it utilize space ? Post: 303013387

Sponsored Content

Operating Systems Solaris Understanding ZFS Snapshots - why will it utilize space ? Post 303013387 by Peasant on Tuesday 20th of February 2018 03:34:50 PM

02-20-2018

Moderator

After the deletion of file1 USEDSNAP is telling you that there are pointers to 100MB of data.
In that time, 2 references exist in point in time for 100M of data.
snap1 - file1
snap2 - file1, file2

USED space in zpool has not changed after the deletion of file1.

Now, tank@snap1 is destroyed.
zfs list is telling you if you destroy the renaming snapshot (snap2), you will reclaim 100M of space as free space.
Since snap2 contains both files (one being 'live' one, other being referenced to) it is using 100M of space in zpool.

During the practice on the blog USEDSNAP column will always be 100M, after first snapshot creation, deletion of file1, second snapshot creation, first snapshot destroy.
This is not displayed clearly on the blog entry.

A good tehnical read Is it magic? | Oracle Matthew Ahrens' Blog

Hope that helps
Regards
Peasant.

This User Gave Thanks to Peasant For This Post:

Peasant

View Public Profile for Peasant

Find all posts by Peasant

3 More Discussions You Might Find Interesting

1. Solaris

How to utilize the 2nd hard disk space in x86 solaris 5.10

I have 2 hard disks ,one hard disk(40gb) completely for windows Os,and the other(120gb) for solaris Os. In the second hard disk.I have utilised around 10gb for the solaris installation and also partitioned with the available 10gb space for the solaris x86 OS. Now i need to utilise the...

2. Solaris

Recommended Patch Cluster Using ZFS Snapshots

I have a question regarding installing recommended patch clusters via ZFS snapshots. Someone wrote a pretty good blog about it here: Initial Program Load: Live Upgrade to install the recommended patch cluster on a ZFS snapshot The person's article is similar to what I've done in the past. ...

3. Solaris

Permissions to run ZFS Snapshots

Hi, I work as an Oracle Technical consultant (mainly DBA related), and I have used ZFS snapshots on previous projects which has helped me a great deal. I often take snapshots before doing some dev work, and then I can roll it back if I want to start again, or if it goes pear shaped!! I have...

LEARN ABOUT OSF1

install-solaris

install-solaris(1M)													       install-solaris(1M)

NAME

       install-solaris - install the Solaris operating system

SYNOPSIS

       install-solaris

       install-solaris	invokes  the  Solaris  Install	program. Depending on graphical capability and available memory at the time of invocation,
       install-solaris invokes either a text-based installer or a graphical installer.

       The following minimum requirements for physical memory dictate which features are available during installation:

       For SPARC machines:

       128 MB

	   Minimum physical memory for all installation types

       128 MB

	   Minimum physical memory required for windowing system

       384 MB

	   Minimum physical memory required for graphical-based installation

       For x86 machines:

       256 MB

	   Minimum physical memory for all installation types

       256 MB

	   Minimum physical memory required for windowing system

       512 MB

	   Minimum physical memory required for graphical-based installation

       In some cases, even if the minimum physical memory is present, available virtual memory after system startup can limit the number  of  fea-
       tures available.

       install-solaris	exists	only  on  the Solaris installation media (CD or DVD) and should be invoked only from there. Refer to the  for more
       details.

       install-solaris allows installation of the operating system onto any standalone system. install-solaris loads the software available on the
       installation media. Refer to the  for disk space requirements.

       Refer to the  for more information on the various menus and selections.

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcdrom  (Solaris instal-  |
       |			     |lation media)		   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Evolving			   |
       +-----------------------------+-----------------------------+

       pkginfo(1), install(1M), pkgadd(1M), attributes(5)

       It is advisable to exit install-solaris by means of the exit options in the install-solaris menus.

								    23 Sep 2005 					       install-solaris(1M)