Bug 1240549
| Summary: | Display ancestors and descendants for thin snapshot/origin LVs even after dependency chain is broken after removing some LVs | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 7 | Reporter: | Peter Rajnoha <prajnoha> |
| Component: | lvm2 | Assignee: | Peter Rajnoha <prajnoha> |
| lvm2 sub component: | Thin Provisioning | QA Contact: | cluster-qe <cluster-qe> |
| Status: | CLOSED ERRATA | Docs Contact: | |
| Severity: | low | ||
| Priority: | medium | CC: | agk, cmarthal, heinzm, jbrassow, msnitzer, prajnoha, prockai, rbednar, slevine, thornber, zkabelac |
| Version: | 7.2 | Keywords: | Triaged |
| Target Milestone: | rc | ||
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | lvm2-2.02.152-1.el7 | Doc Type: | Enhancement |
| Doc Text: |
LVM can now track and display thin snapshot logical volumes that have been removed
You can now configure your system to track thin snapshot logical volumes that have been removed by enabling the `record_lvs_history` metadata option in the `lvm.conf` configuration file. This allows you to display a full thin snapshot dependency chain that includes logical volumes that have been removed from the original dependency chain and have become historical logical volumes. The full dependency chain, including historical LVs, can be displayed with new lv_full_ancestors and lv_full_descendants reporting fields. For information on configuring and displaying historical logical volumes, see https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Logical_Volume_Manager_Administration/LV.html#historical_volumes
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | 2016-11-04 04:09:58 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
| Bug Depends On: | |||
| Bug Blocks: | 1163895, 1295577, 1313485 | ||
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Description
Peter Rajnoha
2015-07-07 08:30:20 UTC
The code is in this devel branch: https://git.fedorahosted.org/cgit/lvm2.git/log/?h=dev-prajnoha-track-removed-lvs It's quite late in the process now - the patchset grew more than I expected - it's adding proper internal interface to handle removed entries (which allows for them to be processed in a very similar way as live entries, making the code consistent). Also, this patchset introduces changes to metadata (new section to keep records about removed LVs). The change may be risky and it's better to have this tested more in Fedora/rawhide first before adding this into RHEL. Though the code in devel branch is finished, it needs thorough review and testing. I'm moving this to 7.3. Adding QA ACK for 7.3. Test as shown in 1240518. The patchset is now upstream since lvm2 v2.02.145.
Summary of changes (taken from WHATS_NEW):
- Make it possible to use lvremove and lvrename on historical LVs.
- For historical LVs, report 'none' for lv_layout and 'history' for lv_role.
- Add full_{ancestors,descendants} fields to report LV ancestry with history.
- Report (h)istorical state within 5th bit (State) of the lv_attr field.
- Add lv_historical reporting field to report if LV is historical or not.
- Add lv_time_removed reporting field to display removal time for hist. LVs.
- Report lv_name, lv_uuid, vg_name, lv_time for historical LVs.
- Add --nohistory switch to lvremove to disable history recording on demand.
- Add -H|--history switch to lvs and lvdisplay to include historical LVs.
- Create historical LVs out of removed thin snapshot LVs and record in history.
- Add metadata/lvs_history_retention_time for automatic removal of hist. LVs.
- Add metadata/record_lvs_history config for switching LV history recording.
- Add support and infrastructure for tracking historical LVs.
For example:
# vgcreate vg /dev/sda
Volume group "vg" successfully created
[1] fedora/~ # lvcreate -l100%FREE -T vg/pool
Logical volume "pool" created.
[1] fedora/~ # lvcreate -V1 -T vg/pool
Rounding up size to full physical extent 4.00 MiB
Logical volume "lvol1" created.
[1] fedora/~ # lvcreate -s vg/lvol1
Logical volume "lvol2" created.
[1] fedora/~ # lvcreate -s vg/lvol2
Logical volume "lvol3" created.
[1] fedora/~ # lvcreate -s vg/lvol3
Logical volume "lvol4" created.
[1] fedora/~ # lvcreate -s vg/lvol3
Logical volume "lvol5" created.
(reporint thin snapshot chain - full_ancestors == ancestors and full_descendants == descendants still)
[1] fedora/~ # lvs -o name,full_ancestors,full_descendants vg
LV FAncestors FDescendants
lvol1 lvol2,lvol3,lvol4,lvol5
lvol2 lvol1 lvol3,lvol4,lvol5
lvol3 lvol2,lvol1 lvol4,lvol5
lvol4 lvol3,lvol2,lvol1
lvol5 lvol3,lvol2,lvol1
pool
[1] fedora/~ # lvs -o name,ancestors,descendants vg
LV Ancestors Descendants
lvol1 lvol2,lvol3,lvol4,lvol5
lvol2 lvol1 lvol3,lvol4,lvol5
lvol3 lvol2,lvol1 lvol4,lvol5
lvol4 lvol3,lvol2,lvol1
lvol5 lvol3,lvol2,lvol1
pool
(removing vg/lvol3 will cause lvol3 to become "historical LV")
[1] fedora/~ # lvremove -ff vg/lvol3
Logical volume "lvol3" successfully removed
(reporting LVs, not including historical LVs, but the original chain is still preserved - that's difference from the older lvs -o ancestors,descendants)
[1] fedora/~ # lvs -o name,ancestors,descendants vg
LV Ancestors Descendants
lvol1 lvol2
lvol2 lvol1
lvol4
lvol5
pool
[1] fedora/~ # lvs -o name,full_ancestors,full_descendants vg
LV FAncestors FDescendants
lvol1 lvol2,lvol4,lvol5
lvol2 lvol1 lvol4,lvol5
lvol4 lvol2,lvol1
lvol5 lvol2,lvol1
pool
(using -H to include historical LVs in report)
[1] fedora/~ # lvs -H -o name,full_ancestors,full_descendants vg
LV FAncestors FDescendants
lvol1 lvol2,-lvol3,lvol4,lvol5
lvol2 lvol1 -lvol3,lvol4,lvol5
-lvol3 lvol2,lvol1 lvol4,lvol5
lvol4 -lvol3,lvol2,lvol1
lvol5 -lvol3,lvol2,lvol1
pool
(if there's no live LV following in the chain, historical LV is removed automatically from history)
[1] fedora/~ # lvremove -ff vg/lvol4
Automatically removing historical logical volume vg/-lvol4.
Logical volume "lvol4" successfully removed
(historical LVs can be referenced by vgname/-lvname, there's also 'h' in 5th bit of the lv_attr field for historical LVs)
[1] fedora/~ # lvs -H vg/-lvol3
LV VG Attr LSize
-lvol3 vg ----h----- 0
(historical LVs can be removed directly by lvremove)
[1] fedora/~ # lvremove -ff vg/-lvol3
Historical logical volume "lvol3" successfully removed
(and if the removed historical LVs is the very last historical LV that preserved the chain, the chain is now broken because we don't have history for the chain anymore)
[1] fedora/~ # lvs -o name,full_ancestors,full_descendants vg
LV FAncestors FDescendants
lvol1 lvol2
lvol2 lvol1
lvol4
lvol5
pool
(let's create snapshot for vg/lvol5 now)
[1] fedora/~ # lvcreate -s vg/lvol5
Logical volume "lvol6" created.
(we can report removal time for historical LVs)
[1] fedora/~ # lvs -H -o name,full_ancestors,full_descendants,time_removed vg
LV FAncestors FDescendants RTime
lvol1 lvol2
lvol2 lvol1
lvol4
-lvol5 lvol6 2016-03-14 14:14:32 +0100
lvol6 -lvol5
pool
(now, setting metadata/lvs_history_retention_time=10 - that means keep history records for 10 seconds per each history item)
[1] fedora/~ # lvmconfig metadata/lvs_history_retention_time
lvs_history_retention_time=10
(see that the current time is more than 10 seconds after removal time)
[1] fedora/~ # date
Mon Mar 14 14:16:31 CET 2016
(...and now any VG write operation that follows will remove outdated historical LVs automatically - I'll use vgchange --addtag which certainly changes metadata, but any command doing VG write will do this. In this case the historiacl LV vg/-lvol5 is removed automtically from history)
[1] fedora/~ # lvs -H -o name,full_ancestors,full_descendants vg
LV FAncestors FDescendants
lvol1 lvol2
lvol2 lvol1
lvol4
lvol6
pool
This bug was accidentally moved from POST to MODIFIED via an error in automation, please see mmccune with any questions Marking as verified in lvm2-2.02.160-1.el7.x86_64
1) Change lvm.conf
Enable metadata section and set following options:
metadata {
record_lvs_history = 1
lvs_history_retention_time = 3600
}
2) Testing layout
# lvs -o lv_name,full_descendants,full_ancestors,lv_layout,lv_role,lv_attr vg
LV FDescendants FAncestors Layout Role Attr
lvol1 lvol2,lvol3,lvol4,lvol5 thin,sparse public,origin,thinorigin Vwi-a-tz--
lvol2 lvol3,lvol4,lvol5 lvol1 thin,sparse public,origin,thinorigin,snapshot,thinsnapshot Vwi---tz-k
lvol3 lvol4,lvol5 lvol2,lvol1 thin,sparse public,origin,thinorigin,multithinorigin,snapshot,thinsnapshot Vwi---tz-k
lvol4 lvol3,lvol2,lvol1 thin,sparse public,snapshot,thinsnapshot Vwi---tz-k
lvol5 lvol3,lvol2,lvol1 thin,sparse public,snapshot,thinsnapshot Vwi---tz-k
pool thin,pool private twi-aotz--
3) Descendants and ancestors matching full_descandants and full_ancestors
# lvs -o lv_name,descendants,ancestors vg
LV Descendants Ancestors
lvol1 lvol2,lvol3,lvol4,lvol5
lvol2 lvol3,lvol4,lvol5 lvol1
lvol3 lvol4,lvol5 lvol2,lvol1
lvol4 lvol3,lvol2,lvol1
lvol5 lvol3,lvol2,lvol1
pool
4) Remove LV
# lvremove -ff vg/lvol3
Logical volume "lvol3" successfully removed
# lvs -o lv_name,descendants,ancestors vg
LV Descendants Ancestors
lvol1 lvol2
lvol2 lvol1
lvol4
lvol5
pool
5) Check full_{ascendants|descendants} contain full LV listing
# lvs -o lv_name,full_descendants,full_ancestors vg
LV FDescendants FAncestors
lvol1 lvol2,lvol4,lvol5
lvol2 lvol4,lvol5 lvol1
lvol4 lvol2,lvol1
lvol5 lvol2,lvol1
pool
6) Check full_{ascendants|descendants} contain historical LVs with -H|--history option
# lvs -H -o lv_name,full_descendants,full_ancestors,lv_layout,lv_role,lv_attr,lv_historical vg
LV FDescendants FAncestors Layout Role Attr Historical
lvol1 lvol2,-lvol3,lvol4,lvol5 thin,sparse public,origin,thinorigin Vwi-a-tz--
lvol2 -lvol3,lvol4,lvol5 lvol1 thin,sparse public,snapshot,thinsnapshot Vwi---tz-k
-lvol3 lvol4,lvol5 lvol2,lvol1 none public,history ----h----- historical
lvol4 -lvol3,lvol2,lvol1 thin,sparse public Vwi---tz-k
lvol5 -lvol3,lvol2,lvol1 thin,sparse public Vwi---tz-k
pool thin,pool private twi-aotz--
7) lv_time_removed attribute
# lvs -H -o lv_name,full_descendants,full_ancestors,lv_layout,lv_role,lv_attr,lv_historical,lv_time_removed vg
LV FDescendants FAncestors Layout Role Attr Historical RTime
lvol1 lvol2,-lvol3,lvol4,lvol5 thin,sparse public,origin,thinorigin Vwi-a-tz--
lvol2 -lvol3,lvol4,lvol5 lvol1 thin,sparse public,snapshot,thinsnapshot Vwi---tz-k
-lvol3 lvol4,lvol5 lvol2,lvol1 none public,history ----h----- historical 2016-07-19 12:06:08 +0200
lvol4 -lvol3,lvol2,lvol1 thin,sparse public Vwi---tz-k
lvol5 -lvol3,lvol2,lvol1 thin,sparse public Vwi---tz-k
pool thin,pool private twi-aotz--
8) lvremove --nohistory option
# lvremove --nohistory vg/lvol2 -ff
Logical volume "lvol2" successfully removed
# lvs --history -o lv_name,full_descendants,full_ancestors,lv_layout,lv_role,lv_attr,lv_historical,lv_time_removed vg
LV FDescendants FAncestors Layout Role Attr Historical RTime
lvol1 thin,sparse public Vwi-a-tz--
-lvol3 lvol4,lvol5 none public,history ----h----- historical 2016-07-19 12:06:08 +0200
lvol4 -lvol3 thin,sparse public Vwi---tz-k
lvol5 -lvol3 thin,sparse public Vwi---tz-k
pool thin,pool private twi-aotz--
Notes:
I) lvs history is turned off by default to prevent filling up metadata area
II) historical LVs acquire a hyphen as a prefix (e.g. '-lvol1')
III) historical LVs get removed once the lvs_history_retention_time is expired
IV) historical LVs can also be removed manually by lvremove (see man lvremove for more)
V) lvremove on historical LVs also removes all lvs in the chain if no existing ancestor or descendant is linked to them
example:
# lvs -o lv_name,full_descendants,full_ancestors vg -H
LV FDescendants FAncestors
-lvol1 -lvol2,-lvol3,lvol4
-lvol2 -lvol3,lvol4 -lvol1
-lvol3 lvol4 -lvol2,-lvol1
lvol4 -lvol3,-lvol2,-lvol1
pool
# lvremove vg/lvol4 -ff
Automatically removing historical logical volume vg/-lvol1.
Automatically removing historical logical volume vg/-lvol2.
Automatically removing historical logical volume vg/-lvol3.
Automatically removing historical logical volume vg/-lvol4.
Logical volume "lvol4" successfully removed
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://rhn.redhat.com/errata/RHBA-2016-1445.html |