Having snapshot technology is great. Who else supports it?
Thanks.
Scott
On 8/22/07, Scott Ehrlich scott@mit.edu wrote:
Having snapshot technology is great. Who else supports it?
Try EqualLogic. I'm pretty sure they do snapshots.
Thanks, Scott
On Wed, Aug 22, 2007 at 12:01:53PM -0500, Scott Moseman wrote:
On 8/22/07, Scott Ehrlich scott@mit.edu wrote:
Having snapshot technology is great. Who else supports it?
Try EqualLogic. I'm pretty sure they do snapshots.
Yep, Equallogic supports snapshots, replication, and all that. and it does them well.
-- Pasi
Scott Ehrlich wrote:
Having snapshot technology is great. Who else supports it?
it can be done at two levels, file system or block.
many SAN (block level) devices have snapshots, including most of the LSI Logic Engenio stuff (resold by IBM, Sun, others), EMC, Intransa, Equalogic, etc.
NAS devices are really just file servers, so could have snapshot implemented either in their backing block storage devices or as a feature of their volume management or file system. NetworkAppliance supports this natively, so do generic OS's like Linux (with LVM), Solaris (with ZFS), which are often used as the innards of NAS systems.
From: centos-bounces@centos.org on behalf of Scott Ehrlich
Having snapshot technology is great. Who else supports it?
EMC supports several levels of snaps with their SnapView layered product. See their product page at http://www.emc.com/products/software/snapview2.jsp
We didn't buy it, but that's because we are only doing VMware ESX direct attached hosts, with a single host per CLARiiON, and I'm using VMware's snapshots for those instances where I need snaps. Not getting SnapView meant I could get more terabytes. -- Lamar Owen Chief Information Officer Pisgah Astronomical Research Institute 1 PARI Drive Rosman, NC 28772 828-862-5554 www.pari.edu
On 8/22/07, Scott Ehrlich scott@mit.edu wrote:
Having snapshot technology is great. Who else supports it?
Roll your own:
http://www.mikerubel.org/computers/rsync_snapshots/ http://www.dirvish.org/
Jiann-Ming Su wrote:
On 8/22/07, Scott Ehrlich scott@mit.edu wrote:
Having snapshot technology is great. Who else supports it?
Roll your own:
http://www.mikerubel.org/computers/rsync_snapshots/ http://www.dirvish.org/
those aren't even close to the same thing, more like traditional backups, rsync or dirvish make copies of the original data.
'snapshotting' in this context refers to 'copy on write' technology. taking a snapshot is a very quick process, usually only a couple seconds, and no data actually gets copied. when the file system is updated while a snapshot is active, THEN the block(s) behind the update are copied to new space, so that there are now two versions of that block, original (snapshot) and new (current). If the snapshot is deleted, these copied blocks are released back into the free pool. if the system is rolled back to the snapshot, the 'new' blocks are released.
A classic use of a snapshot is to make a point-in-time backup of a live system to tape or an external near line disk storage system... you snapshot the file system, let the applications keep running on the live system, and backup the snapshot to your archival storage, then drop the snapshot. Another use is as a checkpoint before doing something risky, like a system update. snapshot the system, install the updates and test them. if there's a problem, rollback to the snapshot.
Scott Ehrlich wrote:
Having snapshot technology is great. Who else supports it?
Zfs on solaris/opensolaris has them. http://docs.sun.com/app/docs/doc/819-5461/6n7ht6qs9?a=view
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Jiann-Ming Su -
John R Pierce -
Lamar Owen -
Les Mikesell -
Pasi Kärkkäinen -
Scott Ehrlich -
Scott Moseman