Re: [zfs-discuss] snapshot question
Thank you James, exactly the answer I needed. Regards, Mark On Jul 29, 2010 3:05pm, James Dickens wrote: On Thu, Jul 29, 2010 at 11:50 AM, Mark white...@gmail.com> wrote: I'm trying to understand how snapshots work in terms of how I can use them for recovering and/or duplicating virtual machines, and how I should set up my file system. I want to use OpenSolaris as a storage platform with NFS/ZFS for some development VMs; that is, the VMs use the OpenSolaris box as their NAS for shared access. Should I set up a separate ZFS file system for each VM so I can individually snapshot each one on a regular basis, or does it matter? The goal would be to be able to take an individual VM back to a previous point in time without changing the others. you can put multiple guests in a single filesystem and use them as a baseline install, then clone it for each new guest, but then you have several baseline guests in the fiilesystem which ZFS is fine with, but may be confusing for the user... linux_base windows_base solaris_base.. all show up in every clone, if you put one guest baseline in each filesystem and clone then you will only see one in each clone and of course you can rename the directories in the clones to match what you want. you need to clone a filesystem per guest because ZFS can only rollback full filesystems, not invidual files. your VM solution may have finer tuned controlls for its own snapshots but those are don't use ZFS' abililities. James Dickens uadmin.blogspot.com Thanks -- This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] snapshot question
On Thu, Jul 29, 2010 at 11:50 AM, Mark wrote: > I'm trying to understand how snapshots work in terms of how I can use them > for recovering and/or duplicating virtual machines, and how I should set up > my file system. > > I want to use OpenSolaris as a storage platform with NFS/ZFS for some > development VMs; that is, the VMs use the OpenSolaris box as their NAS for > shared access. > > Should I set up a separate ZFS file system for each VM so I can > individually snapshot each one on a regular basis, or does it matter? The > goal would be to be able to take an individual VM back to a previous point > in time without changing the others. > > you can put multiple guests in a single filesystem and use them as a baseline install, then clone it for each new guest, but then you have several baseline guests in the fiilesystem which ZFS is fine with, but may be confusing for the user... linux_base windows_base solaris_base.. all show up in every clone, if you put one guest baseline in each filesystem and clone then you will only see one in each clone and of course you can rename the directories in the clones to match what you want. you need to clone a filesystem per guest because ZFS can only rollback full filesystems, not invidual files. your VM solution may have finer tuned controlls for its own snapshots but those are don't use ZFS' abililities. James Dickens uadmin.blogspot.com > Thanks > -- > This message posted from opensolaris.org > ___ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss > ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
[zfs-discuss] snapshot question
I'm trying to understand how snapshots work in terms of how I can use them for recovering and/or duplicating virtual machines, and how I should set up my file system. I want to use OpenSolaris as a storage platform with NFS/ZFS for some development VMs; that is, the VMs use the OpenSolaris box as their NAS for shared access. Should I set up a separate ZFS file system for each VM so I can individually snapshot each one on a regular basis, or does it matter? The goal would be to be able to take an individual VM back to a previous point in time without changing the others. Thanks -- This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Snapshot question
On Nov 13, 2009, at 10:36 PM, Tristan Ball wrote: I think the exception may be when doing a recursive snapshot - ZFS appears to halt IO so that it can take all the snapshots at the same instant. Snapshots cause a txg commit, similar to what you get when you run sync. The time required to commit depends on many factors, perhaps the largest of which is the latency of the disk. At least, that's what it looked like to me. I've got an Opensolaris ZFS box providing NFS to VMWare, and I was getting SCSI timeout's within the Virtual Machines that appeared to happen exactly as the snapshots were taken. SCSI timeouts?!? How short are their timeouts? By default in Solaris, SCSI timeouts are 60 seconds. Have you seen a recursive snapshot take more than 60 seconds? When I turned off the recursive snapshots, and rather had each FS snapshot individually, the problem went away. There have been performance tweeks over the past few years which can impact snapshot performance, though it is still largely gated by the disk. What release were you running? -- richard Regards, Tristan. -Original Message- From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss-boun...@opensolaris.org ] On Behalf Of Richard Elling Sent: Saturday, 14 November 2009 5:02 AM To: Rodrigo E. De León Plicet Cc: zfs-discuss@opensolaris.org Subject: Re: [zfs-discuss] Snapshot question On Nov 13, 2009, at 6:43 AM, Rodrigo E. De León Plicet wrote: While reading about NILFS here: http://www.linux-mag.com/cache/7345/1.html I saw this: One of the most noticeable features of NILFS is that it can "continuously and automatically save instantaneous states of the file system without interrupting service". NILFS refers to these as checkpoints. In contrast, other file systems such as ZFS, can provide snapshots but they have to suspend operation to perform the snapshot operation. NILFS doesn't have to do this. The snapshots (checkpoints) are part of the file system design itself. I don't think that's correct. Can someone clarify? It sounds to me like they confused Solaris UFS with ZFS. What they say applies to UFS, but not ZFS. -- richard ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __ ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Snapshot question
I think the exception may be when doing a recursive snapshot - ZFS appears to halt IO so that it can take all the snapshots at the same instant. At least, that's what it looked like to me. I've got an Opensolaris ZFS box providing NFS to VMWare, and I was getting SCSI timeout's within the Virtual Machines that appeared to happen exactly as the snapshots were taken. When I turned off the recursive snapshots, and rather had each FS snapshot individually, the problem went away. Regards, Tristan. -Original Message- From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss-boun...@opensolaris.org] On Behalf Of Richard Elling Sent: Saturday, 14 November 2009 5:02 AM To: Rodrigo E. De León Plicet Cc: zfs-discuss@opensolaris.org Subject: Re: [zfs-discuss] Snapshot question On Nov 13, 2009, at 6:43 AM, Rodrigo E. De León Plicet wrote: > While reading about NILFS here: > > http://www.linux-mag.com/cache/7345/1.html > > > I saw this: > > One of the most noticeable features of NILFS is that it can > "continuously and automatically save instantaneous states of the > file system without interrupting service". NILFS refers to these as > checkpoints. In contrast, other file systems such as ZFS, can > provide snapshots but they have to suspend operation to perform the > snapshot operation. NILFS doesn't have to do this. The snapshots > (checkpoints) are part of the file system design itself. > > I don't think that's correct. Can someone clarify? It sounds to me like they confused Solaris UFS with ZFS. What they say applies to UFS, but not ZFS. -- richard ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __ ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Snapshot question
On Nov 13, 2009, at 6:43 AM, Rodrigo E. De León Plicet wrote: While reading about NILFS here: http://www.linux-mag.com/cache/7345/1.html I saw this: One of the most noticeable features of NILFS is that it can "continuously and automatically save instantaneous states of the file system without interrupting service". NILFS refers to these as checkpoints. In contrast, other file systems such as ZFS, can provide snapshots but they have to suspend operation to perform the snapshot operation. NILFS doesn’t have to do this. The snapshots (checkpoints) are part of the file system design itself. I don't think that's correct. Can someone clarify? It sounds to me like they confused Solaris UFS with ZFS. What they say applies to UFS, but not ZFS. -- richard ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Snapshot question
>While reading about NILFS here: > >http://www.linux-mag.com/cache/7345/1.html > > >I saw this: > >*One of the most noticeable features of NILFS is that it can "continu= >ously >> and automatically save instantaneous states of the file system with= >out >> interrupting service". NILFS refers to these as checkpoints. In con= >trast, >> other file systems such as ZFS, can provide snapshots but they have= > to suspend >> operation to perform the snapshot operation. NILFS doesn=E2=80=99t = >have to do >> this. The snapshots (checkpoints) are part of the file system desig= >n itself. >> * >> > >I don't think that's correct. Can someone clarify? No, and they also write this: >More over, creating these checkpoints or snapshots do not result >in decreased performance as they do for file systems such as ZFS. Both are wrong; a snapshot is cheap and doesn't suspend operations. It's pretty much like the checkpoints in NILFS. Casper ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
[zfs-discuss] Snapshot question
While reading about NILFS here: http://www.linux-mag.com/cache/7345/1.html I saw this: *One of the most noticeable features of NILFS is that it can "continuously > and automatically save instantaneous states of the file system without > interrupting service". NILFS refers to these as checkpoints. In contrast, > other file systems such as ZFS, can provide snapshots but they have to suspend > operation to perform the snapshot operation. NILFS doesn’t have to do > this. The snapshots (checkpoints) are part of the file system design itself. > * > I don't think that's correct. Can someone clarify? ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
