Re: [zfs-discuss] zfs iscsi storage for virtual machines
I have hundreds of Xen-based virtual machines running off a ZFS/iSCSI service; yes, it's viable. I can't speak for CentOS specifically; our infrastructure is using Debian Etch with our own build of Xen. How does ZFS handle snapshots of large files like VM images? Is replication done on the bit/block level or by file? In otherwords, does a snapshot of a changed VM image take up the same amount of space as the image or only the amount of space of the bits that have changed within the image? I'm also strongly considering going with NFS or AFS instead of iSCSI so I don't have to deal with management of an extra filesystem layer. The VMWare community is split on which is faster. Are there any significant benefits to either one on the ZFS side? ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] zfs iscsi storage for virtual machines
How does ZFS handle snapshots of large files like VM images? Is replication done on the bit/block level or by file? In otherwords, does a snapshot of a changed VM image take up the same amount of space as the image or only the amount of space of the bits that have changed within the image? ZFS uses Copy On Write to implement snap shots. No replication is done. When changes are made only the blocks changed are different (the originals are kept by the snapshot). Neil. ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] zfs iscsi storage for virtual machines
[EMAIL PROTECTED] wrote on 17/07/2007 05:12:49 AM: I'm going to be setting up about 6 virtual machines (Windows Linux) in either VMWare Server or Xen on a CentOS 5 box. I'd like to connect to a ZFS iSCSI target to store the vm images and be able to use zfs snapshots for backup. I have no experience with ZFS, so I have a couple of questions before I move forward. 1. Is this a feasible setup? If not, is there any way to make something like this work reliably? 2. Since I'd most likely want to restore single machines at a time, is it best to have a zpool for each machine? Any insight is appreciated. I have hundreds of Xen-based virtual machines running off a ZFS/iSCSI service; yes, it's viable. I can't speak for CentOS specifically; our infrastructure is using Debian Etch with our own build of Xen. Your success criteria are: 1. Staggering virtual machine cron entries to avoid high I/O contention, 2. Reliable gigabit/10gigabit switching infrastructure. Skimp on this and your project is sunk. Use a high-quality managed switch, good NICs, and well manufactured cables. 3. If using a smart, battery-backed, order-preserving storage array, append set zfs:zfs_nocacheflush = 1 (sans quotes) to /etc/system. Splitting your storage into multiple zpools will just cause wastage and administrative complexity. I strongly advise using a single zpool. JG This email, including any attachments, is intended only for the use of the individual or entity named above and may contain information that is confidential and privileged. Any information contained in this email is not to be used or disclosed for any purpose other than the purpose for which you received it. If you are not the intended recipient you are notified that disclosing, copying, distributing or taking any action in reliance on the contents of this information is strictly prohibited. If you have received this email by mistake, please delete this email permanently from your system. WARNING: Although Editure has taken reasonable precautions to ensure no viruses are present in this email, Editure can not accept responsibility for any losses or damages whatsoever, arising from the use of this email and/or its attachments. www.editure.com ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
[zfs-discuss] zfs iscsi storage for virtual machines
I'm going to be setting up about 6 virtual machines (Windows Linux) in either VMWare Server or Xen on a CentOS 5 box. I'd like to connect to a ZFS iSCSI target to store the vm images and be able to use zfs snapshots for backup. I have no experience with ZFS, so I have a couple of questions before I move forward. 1. Is this a feasible setup? If not, is there any way to make something like this work reliably? 2. Since I'd most likely want to restore single machines at a time, is it best to have a zpool for each machine? Any insight is appreciated. -- Pete ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] zfs iscsi storage for virtual machines
I had originally considered something similar, but... for ZFS snapshot abilities, I am leaning more towards zfs-hosted NFS... Most of the other VMs (FreeBSD, for example) can install onto NFS, it wouldn't actually be going over the network, and it would allow file-level restore instead of drive-level restore. Just my untested 2 cents Malachi On 7/16/07, Peter Baumgartner [EMAIL PROTECTED] wrote: I'm going to be setting up about 6 virtual machines (Windows Linux) in either VMWare Server or Xen on a CentOS 5 box. I'd like to connect to a ZFS iSCSI target to store the vm images and be able to use zfs snapshots for backup. I have no experience with ZFS, so I have a couple of questions before I move forward. 1. Is this a feasible setup? If not, is there any way to make something like this work reliably? 2. Since I'd most likely want to restore single machines at a time, is it best to have a zpool for each machine? Any insight is appreciated. -- Pete ___ 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] zfs iscsi storage for virtual machines
Peter Baumgartner wrote: I'm going to be setting up about 6 virtual machines (Windows Linux) in either VMWare Server or Xen on a CentOS 5 box. I'd like to connect to a ZFS iSCSI target to store the vm images and be able to use zfs snapshots for backup. I have no experience with ZFS, so I have a couple of questions before I move forward. 1. Is this a feasible setup? If not, is there any way to make something like this work reliably? Use some sort of data redundancy on the data. The simplest is a mirrored zpoool. 2. Since I'd most likely want to restore single machines at a time, is it best to have a zpool for each machine? I'd recommend one zpool, multiple file systems. That way you can manage each file system (iSCSI target) separately, but still have the flexibility of a large zpool. -- richard ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
