I got stumped by a question that I got while on the road this week, and I thought I’d throw it out. A user came up to me who has a 300 TB Oracle database that generates 3-4 TB of transaction logs a day. They are currently unable to back it up — at all. When I suggested my usual, she shocked me and said that they had tried it. Ouch.
The database in question resides on a V-Max. First let’s talk about what we would do if we treated it like other databases. We would need to back it up at 25 TB/hr to do a typical full backup to tape or disk. That’s simply not going to happen. While there are device configurations that I can think of to make a backup target fast enough to handle that, we couldn’t get it there in time. We certainly can’t do it over IP, and I highly doubt whatever host they have the database on can handle 25 TB/hr (~7000 MB/s, BTW) through their backplane and CPU.
What if we did server-free backup that uses the SCSI 3rd party copy command? Then you’d only have to copy the data via the SAN to the target device. The first problem is that the target device still would have to be monstrous. The second problem is I doubt that the V-Max (although i could be wrong) could generate 7000 MB/s either. But the final problem is actually a V-Max problem. The user in question says that their level of transactions is so high that the cache on the V-Max fills up if they try to take a snapshot. (I was surprised by that as 3-4TB a day is only a 1% change rate.) No snapshot, no server-free backup. It also means no near-CDP either, as that is snapshots and replication.
“CDP!” I shouted. She told me that EMC’s RecoverPoint maxes out at 150 TB. So much for that.
I told her that there are other CDP solutions out there and that they should look at them, but oddly enough “startup” products are really hard to get into this company. (I did give her a really hard time at that point. A product from a startup that solves the problem is still better than nothing, which is what they currently have now.)
The really sad thing is that is database couldn’t be more mission critical to their business. If it ever died, they’d be in a serious world of hurt.
If you think you know how to solve this problem, shout out. As for me, I’m a bit stymied at the moment.
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Written by W. Curtis Preston (@wcpreston). For those of you unfamiliar with my work, I've specialized in backup & recovery since 1993. I've written the O'Reilly books on backup and have worked with a number of native and commercial tools. I am now Chief Technical Evangelist at Druva, the leading provider of cloud-based data protection and data management tools for endpoints, infrastructure, and cloud applications. These posts reflect my own opinion and are not necessarily the opinion of my employer.