Using both shared and local storage
Hello everybody. Currently at the company, we are testing oVirt 3.5 as a cloud platform. We have 4 nodes and GlusterFS as a shared storage. Every node has another SSD disk, currently not used. What we would like is to attach that local storage to particular host, so that some virtual machines can be on local and some on shared storage. If I try to create local storage, it works, but then host is in separate Data Center. If I try to add POSIX FS to node in existing Data Center, then all other hosts stop working, since they can't access that local storage (kind of expected). So, long story short - does shared and local storage mix and how? Thank you very much! -- Damir Marković | System Engineer | Nordeus
From: "Damir Marković" <damirm@nordeus.eu> To: users@ovirt.org Sent: Monday, August 31, 2015 11:44:22 AM Subject: [ovirt-users] Using both shared and local storage
Hello everybody.
Currently at the company, we are testing oVirt 3.5 as a cloud platform. We have 4 nodes and GlusterFS as a shared storage. Every node has another SSD disk, currently not used. What we would like is to attach that local storage to particular host, so that some virtual machines can be on local and some on shared storage. If I try to create local storage, it works, but then host is in separate Data Center. If I try to add POSIX FS to node in existing Data Center, then all other hosts stop working, since they can't access that local storage (kind of expected).
So, long story short - does shared and local storage mix and how?
Thank you very much!
Works as expected, doesn't it? What do you want to exactly achieve with local storage? j.
No, it doesn't work as expected. I would expect to have an option to attach to any Virtual Machine storage which is either shared or local. For example, I have database server so I could put on shared storage and use local, SSD disk for data. I don't care if system is on "slow" network storage but with a lot of space and in the same time, I can use limited, but fast SSD space for data only. So, is this possible or not? On Mon, Aug 31, 2015 at 12:24 PM, Jiri Belka <jbelka@redhat.com> wrote:
From: "Damir Marković" <damirm@nordeus.eu> To: users@ovirt.org Sent: Monday, August 31, 2015 11:44:22 AM Subject: [ovirt-users] Using both shared and local storage
Hello everybody.
Currently at the company, we are testing oVirt 3.5 as a cloud platform. We have 4 nodes and GlusterFS as a shared storage. Every node has another SSD disk, currently not used. What we would like is to attach that local storage to particular host, so that some virtual machines can be on local and some on shared storage. If I try to create local storage, it works, but then host is in separate Data Center. If I try to add POSIX FS to node in existing Data Center, then all other hosts stop working, since they can't access that local storage (kind of expected).
So, long story short - does shared and local storage mix and how?
Thank you very much!
Works as expected, doesn't it? What do you want to exactly achieve with local storage?
j.
-- Damir Marković | System Engineer | Nordeus
No, it doesn't work as expected. I would expect to have an option to attach to any Virtual Machine storage which is either shared or local.
It does work as expected, do your homework first to know how oVirt does work. Your expectation are just your expectations. Question: How would you migrate a VM in a cluster with local storage? Wouldn't glusterfs solve the issue? It can use those SSDs... (Not expert in glusters here...). j.
For example, I have database server so I could put on shared storage and use local, SSD disk for data. I don't care if system is on "slow" network storage but with a lot of space and in the same time, I can use limited, but fast SSD space for data only.
So, is this possible or not?
[...]
Currently at the company, we are testing oVirt 3.5 as a cloud platform. We have 4 nodes and GlusterFS as a shared storage. Every node has another SSD disk, currently not used. What we would like is to attach that local storage to particular host, so that some virtual machines can be on local and some on shared storage. If I try to create local storage, it works, but then host is in separate Data Center. If I try to add POSIX FS to node in existing Data Center, then all other hosts stop working, since they can't access that local storage (kind of expected).
So, long story short - does shared and local storage mix and how?
Thank you very much!
Works as expected, doesn't it? What do you want to exactly achieve with local storage?
Thank you for your help, Jiri! My expectations are based on experience with other cloud platforms and since oVirt doesn't work like that, we simply won't use it. :-) My post was simply for purpose to see if I am missing something, but you confirmed that I am not. Once again, thank you a lot! On Mon, Aug 31, 2015 at 12:38 PM, Jiri Belka <jbelka@redhat.com> wrote:
No, it doesn't work as expected. I would expect to have an option to attach to any Virtual Machine storage which is either shared or local.
It does work as expected, do your homework first to know how oVirt does work. Your expectation are just your expectations.
Question: How would you migrate a VM in a cluster with local storage?
Wouldn't glusterfs solve the issue? It can use those SSDs... (Not expert in glusters here...).
j.
For example, I have database server so I could put on shared storage and use local, SSD disk for data. I don't care if system is on "slow" network storage but with a lot of space and in the same time, I can use limited, but fast SSD space for data only.
So, is this possible or not?
Currently at the company, we are testing oVirt 3.5 as a cloud
We have 4 nodes and GlusterFS as a shared storage. Every node has another SSD disk, currently not used. What we would
[...] platform. like
is to
attach that local storage to particular host, so that some virtual machines can be on local and some on shared storage. If I try to create local storage, it works, but then host is in separate Data Center. If I try to add POSIX FS to node in existing Data Center, then all other hosts stop working, since they can't access that local storage (kind of expected).
So, long story short - does shared and local storage mix and how?
Thank you very much!
Works as expected, doesn't it? What do you want to exactly achieve with local storage?
-- Damir Marković | System Engineer | Nordeus
From: "Damir Marković" <damirm@nordeus.eu> To: "Jiri Belka" <jbelka@redhat.com> Cc: users@ovirt.org Sent: Monday, August 31, 2015 2:02:10 PM Subject: Re: [ovirt-users] Using both shared and local storage
Thank you for your help, Jiri!
My expectations are based on experience with other cloud platforms and since oVirt doesn't work like that, we simply won't use it. :-) My post was simply for purpose to see if I am missing something, but you confirmed that I am not.
Once again, thank you a lot!
It is similar as assigning physical network card and then doing migration of virtual VM. Before NPIV for FC, I used to assign physical FC card to LPARs (IBM PowerVM virtualization solution) but then it was not possible to move the LPAR (VM). But it was supported. If you feel strong that it should be possible to have a VM with a disk on shared storage and on local storage as well, just create a RFE in oVirt bugzilla. I could imagine only use for this, having some "old static" data on such local disk which was synced ouf of oVirt env. j.
Hello Damir.
If I try to create local storage, it works, but then host is in separate Data Center. If I try to add POSIX FS to node in existing Data Center, then all other hosts stop working, since they can't access that local storage (kind of expected).
So, long story short - does shared and local storage mix and how?
We faced the same need - to use a local storage for our CI and managed to use vdsm scratchpad hook for that: http://www.ovirt.org/VDSM-Hooks/scratchpad it implements something similar to AWS ephemeral storage, so it mounts a local disk that does not survive over reboot. This might work for you. Of cause it will not be possible to migrate such a VM and the hook will fails an attempt to do migration. Please note that there is a patch https://gerrit.ovirt.org/#/c/42573/ without which it may not work. This patch was merged, but most like is not yet at the ovirt version you use. Let me know if you have other questions with regards to that hook usage. I may also share my unit files for systemd to format and mount the local storage provided by the hook. Anton.
Thank you, Anton. I will take a look at this, but seems promising. On Mon, Aug 31, 2015 at 2:27 PM, Anton Marchukov <amarchuk@redhat.com> wrote:
Hello Damir.
If I try to create local storage, it works, but then host is in separate Data Center. If I try to add POSIX FS to node in existing Data Center, then all other hosts stop working, since they can't access that local storage (kind of expected).
So, long story short - does shared and local storage mix and how?
We faced the same need - to use a local storage for our CI and managed to use vdsm scratchpad hook for that:
http://www.ovirt.org/VDSM-Hooks/scratchpad
it implements something similar to AWS ephemeral storage, so it mounts a local disk that does not survive over reboot. This might work for you. Of cause it will not be possible to migrate such a VM and the hook will fails an attempt to do migration.
Please note that there is a patch https://gerrit.ovirt.org/#/c/42573/ without which it may not work. This patch was merged, but most like is not yet at the ovirt version you use.
Let me know if you have other questions with regards to that hook usage. I may also share my unit files for systemd to format and mount the local storage provided by the hook.
Anton.
-- Damir Marković | System Engineer | Nordeus
participants (3)
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Anton Marchukov -
Damir Marković -
Jiri Belka