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The case for not Delphix
I’ve recently been exposed to some Delphix marketing. It may be a novel (even cool) product but I wasn’t impressed. Here’s why. Delphix is positioned as a database virtualization product. Databases are virtual already, that is, they aren’t physical things you can touch, they are logical things of which you can have many on a […]
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Distributed systems, High availability
Near instantaneous high availability for databases?
In the study of the availability of computer systems in general, three distributed concepts apply. a) Replication makes multiple (two or more) copies of an application and its data available. If any one copy becomes unavailable due to a failure, the remaining copies remain available. A transaction will typically fail, and upon retrying it will […]
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VMmark is not for sissies
The VMmark benchmark suite from VMWare is very well documented, but it’s still not trivial to get it going. Some things you learn only by ignoring the documentation, getting it wrong and then redoing it correctly: 1) Leave IPv6 switched on, especially on the mail server. 2) Stick to a three part domain name, e.g. […]
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IBM DS8000 write cache – all 6 GB of it
[Migrated post from my old site, comments unfortunately remain behind] There you have it, no reason to continue this post. The DS8000 has 6 GB of write cache. Actually, each server has 6 GB, but you need to mirror writes so that effectively halves the 12 GB total to 6. This is not a readily known […]
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Deduplication: DataDomain vs ProtecTIER – Performance
[Migrated post from my old site, comments unfortunately remain behind] Let’s talk about the performance characteristics of the EMC DataDomain and the IBM ProtecTIER. I had the privilege for some months to have both an EMC DD890 and an IBM TS7650G onsite. Both are close to top of the range and were connected via multiple 8 […]
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Deduplication: DataDomain vs ProtecTIER
[Migrated post from my old site, comments unfortunately remain behind] I’ve been doing some interesting tests on EMC’s DataDomain & IBM’s ProtecTIER. Both are apparently the leaders in the industry on secondary storage deduplication. So our friendly resellers brought us one each to test: an EMC DD890 and an IBM ProtecTIER of some designation (I forget […]