Re: [PVE-User] Proxmox, iSCSI, Mirrored LVM?

[Eneko Lacunza]

Hi Ric,

On 11/12/13 00:27, Ric Moore wrote:

On 12/10/2013 04:01 AM, Eneko Lacunza wrote:

Hi,

Some time ago I did some (non-extensive) tests and I didn't like what I
saw. It seemed LVM wouldn't warn when a RAID1 had a failed disk, LV
seemed to behave wrongly and so on.

If your environment allows it, I recommend to use mdraid, even if your
have to do it on different PV LVs; although it'd be better to use
disk->md->lvm .
This begs the question which is best? We acquired an older Dell server 
and are using the built-in hardware raid server to manage/oversee the 
drives. I'm thinking it's long in the tooth, since it hasn't been 
updated since 2005. Would a software raid be better? Would that 
improve the responsiveness of the Proxmox cluster on it? Thanks, Ric


Currently mdraid is not supported on Proxmox, but my experience says 
that it works quite well. The only caveheat I found is, just don't 
change a RAID1 mirror count (->crash). If you're using big disks, 
remember to activate bitmap to help recoveries :)


Also, if your Dell server RAID card has battery-backed cache, then it 
will give you better performance than mdraid. Otherwise, I like to know 
that with mdraid I can plug the drives on any other linux box to 
read/use the data on them :)


Finally, booting the server with a failed disk drive in a RAID-set could 
prove easier with hardware RAID than with mdraid.


Cheers
Eneko

--
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Binovo IT Human Project, S.L.
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Re: [PVE-User] Proxmox, iSCSI, Mirrored LVM?

[Eneko Lacunza]

Hi,

Some time ago I did some (non-extensive) tests and I didn't like what I 
saw. It seemed LVM wouldn't warn when a RAID1 had a failed disk, LV 
seemed to behave wrongly and so on.


If your environment allows it, I recommend to use mdraid, even if your 
have to do it on different PV LVs; although it'd be better to use 
disk->md->lvm .


Cheers
Eneko

On 08/12/13 11:33, Marco Gabriel wrote:
I never tried this myself, but I think you'll need to use the mirror 
log disk logs instead of the default disk log. Maybe this helps: 
http://www.sandelman.ca/mcr/blog/lvm/


Marco

Am 07.12.13 16:15, schrieb Lex Rivera:
By LVM mirror i mean mirrored LV volumes, distributed on several VGs. 
(PVs is iSCSI-based disks running on two separate servers)

Like RAID1.
On Fri, Dec 6, 2013, at 03:59 PM, Marco Gabriel - inett GmbH wrote:

-Ursprüngliche Nachricht-
> Hello, has anyone tried LVM mirror for storage HA?
> We managed to get mirror running with two iSCSI disks, but when one of
> devices goes offline, test VM acting strange.
What do you mean with LVM mirror?

- LVM on top of DRBD? - you need to use active/active

- mirroring of a specific logical volume?

- mirroring on storage hardware layer? Proxmox shouldn't care then 
if you have iscsi multipathing



best regards

Marco



--
Zuzendari Teknikoa / Director Técnico
Binovo IT Human Project, S.L.
Telf. 943575997
  943493611
Astigarraga bidea 2, planta 6 dcha., ofi. 3-2; 20180 Oiartzun (Gipuzkoa)
www.binovo.es

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Re: [PVE-User] Proxmox, iSCSI, Mirrored LVM?

[Marco Gabriel]

I never tried this myself, but I think you'll need to use the mirror log 
disk logs instead of the default disk log. Maybe this helps: 
http://www.sandelman.ca/mcr/blog/lvm/


Marco

Am 07.12.13 16:15, schrieb Lex Rivera:
By LVM mirror i mean mirrored LV volumes, distributed on several VGs. 
(PVs is iSCSI-based disks running on two separate servers)

Like RAID1.
On Fri, Dec 6, 2013, at 03:59 PM, Marco Gabriel - inett GmbH wrote:

-Ursprüngliche Nachricht-
> Hello, has anyone tried LVM mirror for storage HA?
> We managed to get mirror running with two iSCSI disks, but when one of
> devices goes offline, test VM acting strange.
What do you mean with LVM mirror?

- LVM on top of DRBD? - you need to use active/active

- mirroring of a specific logical volume?

- mirroring on storage hardware layer? Proxmox shouldn't care then if 
you have iscsi multipathing



best regards

Marco


--
*inett GmbH * » Ihr IT Systemhaus in Saarbrücken

Eschberger Weg 1

66121 Saarbrücken
Geschäftsführer: Marco Gabriel
Handelsregister Saarbrücken
HRB 16588


Telefon: 0681 / 41 09 93 – 0 

Telefax: 0681 / 41 09 93 – 99
E-Mail: i...@inett.de 
Web: www.inett.de 

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Center - SEP sesam Certified Partner - Endian Certified Partner - 
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Re: [PVE-User] Proxmox, iSCSI, Mirrored LVM?

[Lex Rivera]

By LVM mirror i mean mirrored LV volumes, distributed on several VGs.
(PVs is iSCSI-based disks running on two separate servers)

Like RAID1.



On Fri, Dec 6, 2013, at 03:59 PM, Marco Gabriel - inett GmbH wrote:

-Ursprüngliche Nachricht-

> Hello, has anyone tried LVM mirror for storage HA?

> We managed to get mirror running with two iSCSI disks, but when one
of
> devices goes offline, test VM acting strange.

What do you mean with LVM mirror?


- LVM on top of DRBD? - you need to use active/active
- mirroring of a specific logical volume?
- mirroring on storage hardware layer? Proxmox shouldn't care then if
you have iscsi multipathing

best regards
Marco



--



inett GmbH » Ihr IT Systemhaus in Saarbrücken

Eschberger Weg 1
66121 Saarbrücken
Geschäftsführer: Marco Gabriel
Handelsregister Saarbrücken
HRB 16588

Telefon: [1]0681 / 41 09 93 – 0
Telefax: 0681 / 41 09 93 – 99
E-Mail: [2]i...@inett.de
Web: [3]www.inett.de

Zarafa Gold Partner - Proxmox Authorized Reseller - Proxmox Training
Center - SEP sesam Certified Partner - Endian Certified Partner -
Kaspersky Silver Partner - Mitglied im iTeam Systemhausverbund für den
Mittelstand

References

1. tel:+49681419930
2. mailto:i...@inett.de
3. http://www.inett.de/
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Re: [PVE-User] Proxmox, iSCSI, Mirrored LVM?

[Marco Gabriel - inett GmbH]

-Ursprüngliche Nachricht-

> Hello, has anyone tried LVM mirror for storage HA?
> We managed to get mirror running with two iSCSI disks, but when one of
> devices goes offline, test VM acting strange.



What do you mean with LVM mirror?

- LVM on top of DRBD? - you need to use active/active
- mirroring of a specific logical volume?
- mirroring on storage hardware layer? Proxmox shouldn't care then if you have 
iscsi multipathing

best regards
Marco



--
inett GmbH»Ihr IT Systemhaus in Saarbrücken
Eschberger Weg 1
66121 Saarbrücken
Geschäftsführer: Marco Gabriel
Handelsregister Saarbrücken
HRB 16588

Telefon: 0681 / 41 09 93 – 0
Telefax: 0681 / 41 09 93 – 99
E-Mail: i...@inett.de  
Web: www.inett.de  

Zarafa Gold Partner - Proxmox Authorized Reseller - Proxmox Training Center - 
SEP sesam Certified Partner - Endian Certified Partner - Kaspersky Silver 
Partner - Mitglied im iTeam Systemhausverbund für den Mittelstand

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[PVE-User] Proxmox, iSCSI, Mirrored LVM?

[Lex Rivera]

Hello, has anyone tried LVM mirror for storage HA?
We managed to get mirror running with two iSCSI disks, but when one of
devices goes offline, test VM acting strange.
Sometimes it _may_ work after one disk failure and connection recovery,
but more common result is VM going to zombie state.
In that case, i cannot even kill process, it continues to work in Zl
state even after sigterm, and the only way to kill that VM (and restart
it as well) is to reboot node (since it still holds descriptor and some
files like VMID.qmp. BTW, what is that "qmp" file?). 
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