[linux-lvm] thin pool and discards

[linux-lvm] thin pool and discards

[Vasiliy Tolstov]

Hello. I'm try to check that discard are working. I have thin volume
1031 (used by virtual machine)
I'm fill the disc and delete data, (fs ext4 with discard option) after
that i manually run fstrim -v /
but data on thin volume not reclaimed.

  LV      VG   Attr       LSize   Pool Origin Data%  Move Log Cpy%Sync Convert
  tp0     vg0  twi-a-tz-- 445.00g               0.00
  373_153 vg1  Vwi---tz-k  20.00g tp1
  375_151 vg1  Vwi---tz-k  40.00g tp1
  529_217 vg1  Vwi---tz-k  40.00g tp1
  531_221 vg1  Vwi---tz-k  20.00g tp1
  533_219 vg1  Vwi---tz-k  40.00g tp1
  577_305 vg1  Vwi---tz-k  40.00g tp1
  581_309 vg1  Vwi---tz-k  40.00g tp1
  583_307 vg1  Vwi---tz-k  20.00g tp1
  tp1     vg1  twi-a-tz-- 445.00g               0.50
  377_159 vg2  Vwi---tz-k  20.00g tp2
  445_197 vg2  Vwi---tz-k  20.00g tp2
  tp2     vg2  twi-a-tz-- 445.00g               0.25
  1031    vg3  Vwi-aotz--  20.00g tp3          56.23
  tp3     vg3  twi-a-tz-- 445.00g               2.53
  tp4     vg4  twi-a-tz-- 445.00g               0.00
  111     vg5  Vwi-aotz--  20.00g tp5           5.63
  111_23  vg5  Vwi---tz-k  20.00g tp5  111
  111_71  vg5  Vwi---tz-k  20.00g tp5  111
  13      vg5  Vwi-aotz--  30.00g tp5           4.70
  17      vg5  Vwi-aotz--  20.00g tp5          25.58
  29      vg5  Vwi-a-tz--  20.00g tp5           0.00
  31      vg5  Vwi-a-tz--  20.00g tp5           0.00
  33      vg5  Vwi-a-tz--  20.00g tp5           0.00
  35      vg5  Vwi-a-tz--  20.00g tp5           0.00
  75      vg5  Vwi-aotz--  20.00g tp5          25.58
  tp5     vg5  twi-a-tz-- 445.00g               2.92

lvm - 2.02.106
kernel 3.10

-- 
Vasiliy Tolstov,
e-mail: v.tolstov@selfip.ru
jabber: vase@selfip.ru

Re: [linux-lvm] thin pool and discards

[Zdenek Kabelac]

Dne 30.9.2014 v 15:26 Vasiliy Tolstov napsal(a):
> Hello. I'm try to check that discard are working. I have thin volume
> 1031 (used by virtual machine)
> I'm fill the disc and delete data, (fs ext4 with discard option) after
> that i manually run fstrim -v /
> but data on thin volume not reclaimed.
>
>    LV      VG   Attr       LSize   Pool Origin Data%  Move Log Cpy%Sync Convert
>    tp0     vg0  twi-a-tz-- 445.00g               0.00
>    373_153 vg1  Vwi---tz-k  20.00g tp1
>    375_151 vg1  Vwi---tz-k  40.00g tp1
>    529_217 vg1  Vwi---tz-k  40.00g tp1
>    531_221 vg1  Vwi---tz-k  20.00g tp1
>    533_219 vg1  Vwi---tz-k  40.00g tp1
>    577_305 vg1  Vwi---tz-k  40.00g tp1
>    581_309 vg1  Vwi---tz-k  40.00g tp1
>    583_307 vg1  Vwi---tz-k  20.00g tp1
>    tp1     vg1  twi-a-tz-- 445.00g               0.50
>    377_159 vg2  Vwi---tz-k  20.00g tp2
>    445_197 vg2  Vwi---tz-k  20.00g tp2
>    tp2     vg2  twi-a-tz-- 445.00g               0.25
>    1031    vg3  Vwi-aotz--  20.00g tp3          56.23
>    tp3     vg3  twi-a-tz-- 445.00g               2.53
>    tp4     vg4  twi-a-tz-- 445.00g               0.00
>    111     vg5  Vwi-aotz--  20.00g tp5           5.63
>    111_23  vg5  Vwi---tz-k  20.00g tp5  111
>    111_71  vg5  Vwi---tz-k  20.00g tp5  111
>    13      vg5  Vwi-aotz--  30.00g tp5           4.70
>    17      vg5  Vwi-aotz--  20.00g tp5          25.58
>    29      vg5  Vwi-a-tz--  20.00g tp5           0.00
>    31      vg5  Vwi-a-tz--  20.00g tp5           0.00
>    33      vg5  Vwi-a-tz--  20.00g tp5           0.00
>    35      vg5  Vwi-a-tz--  20.00g tp5           0.00
>    75      vg5  Vwi-aotz--  20.00g tp5          25.58
>    tp5     vg5  twi-a-tz-- 445.00g               2.92
>
> lvm - 2.02.106
> kernel 3.10
>

Kernel 3.10 is too old,
Please repeat the test with at least 3.16


Zdenek

Re: [linux-lvm] thin pool and discards

[Vasiliy Tolstov]

2014-09-30 18:35 GMT+04:00 Zdenek Kabelac <zkabelac@redhat.com>:
> Kernel 3.10 is too old,
> Please repeat the test with at least 3.16


Why? As i understand 3.10 lts... Can you say me what patches i need to
cherry pick? Or maybe redhat kernel have this feature...?

-- 
Vasiliy Tolstov,
e-mail: v.tolstov@selfip.ru
jabber: vase@selfip.ru

Re: [linux-lvm] thin pool and discards

[Mike Snitzer]

On Tue, Sep 30 2014 at 10:57am -0400,
Vasiliy Tolstov <v.tolstov@selfip.ru> wrote:

> 2014-09-30 18:35 GMT+04:00 Zdenek Kabelac <zkabelac@redhat.com>:
> > Kernel 3.10 is too old,
> > Please repeat the test with at least 3.16
> 
> 
> Why? As i understand 3.10 lts... Can you say me what patches i need to
> cherry pick? Or maybe redhat kernel have this feature...?

You likely need this upstream commit:
http://git.kernel.org/linus/19fa1a6756ed9e92daa9537c03b47d6b55cc2316

Though that commit was tagged for stable.  So not sure.

In general, upstream dm-thinp saw quite a few improvements that in
combination results in a much more stable dm-thinp (particularly error
handling from faults and out of space conditions).

RHEL7 does include these changes.

Re: [linux-lvm] thin pool and discards

[Vasiliy Tolstov]

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2014-09-30 19:49 GMT+04:00 Mike Snitzer <snitzer@redhat.com>:

> You likely need this upstream commit:
> http://git.kernel.org/linus/19fa1a6756ed9e92daa9537c03b47d6b55cc2316
>
> Though that commit was tagged for stable.  So not sure.
>
> In general, upstream dm-thinp saw quite a few improvements that in
> combination results in a much more stable dm-thinp (particularly error
> handling from faults and out of space conditions).
>
> RHEL7 does include these changes.
>

Thanks! Also i'm try to check rhel 7 kernel sources...


-- 
Vasiliy Tolstov,
e-mail: v.tolstov@selfip.ru
jabber: vase@selfip.ru

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Re: [linux-lvm] thin pool and discards

[Vasiliy Tolstov]

2014-09-30 19:49 GMT+04:00 Mike Snitzer <snitzer@redhat.com>:
> You likely need this upstream commit:
> http://git.kernel.org/linus/19fa1a6756ed9e92daa9537c03b47d6b55cc2316
>
> Though that commit was tagged for stable.  So not sure.
>
> In general, upstream dm-thinp saw quite a few improvements that in
> combination results in a much more stable dm-thinp (particularly error
> handling from faults and out of space conditions).
>
> RHEL7 does include these changes.


Thanks! Rhel kernel works fine for me. Does it possible to send needed
patches to stable for all other users ?=) As i see this commit does
not in 3.10 stable now.

-- 
Vasiliy Tolstov,
e-mail: v.tolstov@selfip.ru
jabber: vase@selfip.ru

Re: [linux-lvm] thin pool and discards

[Vasiliy Tolstov]

2014-10-09 2:44 GMT+04:00 Vasiliy Tolstov <v.tolstov@selfip.ru>:
> Thanks! Rhel kernel works fine for me. Does it possible to send needed
> patches to stable for all other users ?=) As i see this commit does
> not in 3.10 stable now.


AS i see i have another issue. I don't know how created some thinp
volumes, but on some of them i'm able to get back space after discard,
but on some not. How can i debug this ?

on vg0 not works:
vgdisplay vg0/tp0
  --- Volume group ---
  VG Name               vg0
  System ID
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  359
  VG Access             read/write
  VG Status             resizable
  MAX LV                10000
  Cur LV                6
  Open LV               2
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               449.70 GiB
  PE Size               4.00 MiB
  Total PE              115124
  Alloc PE / Size       114230 / 446.21 GiB
  Free  PE / Size       894 / 3.49 GiB
  VG UUID               7iCwdw-NTqg-W8dJ-4hTE-8D8J-r9Mv-8y4NVM

lvdisplay vg0/tp0
  --- Logical volume ---
  LV Name                tp0
  VG Name                vg0
  LV UUID                R4ioiK-PWnr-SLUp-8g0l-CTU0-nRn1-bKebI3
  LV Write Access        read/write
  LV Creation host, time cn07, 2014-08-13 19:54:22 +0400
  LV Pool transaction ID 173
  LV Pool metadata       tp0_tmeta
  LV Pool data           tp0_tdata
  LV Pool chunk size     64.00 KiB
  LV Zero new blocks     yes
  LV Status              available
  # open                 0
  LV Size                445.00 GiB
  Allocated pool data    2.97%
  Allocated metadata     1.34%
  Current LE             113920
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           254:39




on vg1 all works fine:

vgdisplay vg1
  --- Volume group ---
  VG Name               vg1
  System ID
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  227
  VG Access             read/write
  VG Status             resizable
  MAX LV                10000
  Cur LV                9
  Open LV               3
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               449.70 GiB
  PE Size               4.00 MiB
  Total PE              115124
  Alloc PE / Size       114230 / 446.21 GiB
  Free  PE / Size       894 / 3.49 GiB
  VG UUID               zbDIA4-731p-3uCm-oHx1-txYu-YMd7-YLMCVj

lvdisplay vg1/tp1
  --- Logical volume ---
  LV Name                tp1
  VG Name                vg1
  LV UUID                aVJpg3-xDYo-0Tuz-fImd-kA3I-Qd3g-e3xRSR
  LV Write Access        read/write
  LV Creation host, time cn07, 2014-08-13 19:54:22 +0400
  LV Pool transaction ID 110
  LV Pool metadata       tp1_tmeta
  LV Pool data           tp1_tdata
  LV Pool chunk size     64.00 KiB
  LV Zero new blocks     yes
  LV Status              available
  # open                 0
  LV Size                445.00 GiB
  Allocated pool data    6.65%
  Allocated metadata     2.68%
  Current LE             113920
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           254:32


-- 
Vasiliy Tolstov,
e-mail: v.tolstov@selfip.ru
jabber: vase@selfip.ru

Re: [linux-lvm] thin pool and discards

[Zdenek Kabelac]

Dne 9.10.2014 v 15:19 Vasiliy Tolstov napsal(a):
> 2014-10-09 2:44 GMT+04:00 Vasiliy Tolstov <v.tolstov@selfip.ru>:
>> Thanks! Rhel kernel works fine for me. Does it possible to send needed
>> patches to stable for all other users ?=) As i see this commit does
>> not in 3.10 stable now.
>
>
> AS i see i have another issue. I don't know how created some thinp
> volumes, but on some of them i'm able to get back space after discard,
> but on some not. How can i debug this ?
>

Please mention which kernel do you use - there have been patches
related to discard on thin volumes (pretty resent - kernel 3.14 I think).

If you use old stable 3.10  from vanilla kernel it simply cannot be compared 
with 3.10  RHEL kernel -  they are very different (RHEL has ton of stuff 
backported even from the latest kernels)

So - please try first with upstream to see if you problem is not already fixed.


Zdenek

Re: [linux-lvm] thin pool and discards

[Vasiliy Tolstov]

2014-10-09 18:19 GMT+04:00 Zdenek Kabelac <zkabelac@redhat.com>:
> Please mention which kernel do you use - there have been patches
> related to discard on thin volumes (pretty resent - kernel 3.14 I think).
>
> If you use old stable 3.10  from vanilla kernel it simply cannot be compared
> with 3.10  RHEL kernel -  they are very different (RHEL has ton of stuff
> backported even from the latest kernels)
>
> So - please try first with upstream to see if you problem is not already
> fixed.


I'm recreate all devices and now all works fine in 3.10.55 and in
rhel. I think my hands bad =(.

-- 
Vasiliy Tolstov,
e-mail: v.tolstov@selfip.ru
jabber: vase@selfip.ru