Category Archives: Opensolaris
Elevator Algorithm II
DO NOT TRY IT IN PRODUCTION. USE AT YOUR OWN RISK! In my last post i did write about some issues related with disksort: 1) Performance (Latency) 2) Consistency In my D Script i’m printing the buf sector when the sd driver receives it. So, without sorting. That’s important because i’m trying to understand why [...]
Elevator Algorithm
Hello there, this will be a long post… so, i think if you have no time to waste, think again before you go ahead. And, no. I’m not Morpheus, so i cannot offer you the truth. Actually, i can just offer you my doubts. And no pills, i do not like them. My blog is [...]
Performance II
In my last post about “Performance“, i did talk about a ZFS tuning parameter: zfs_prefetch_disable. And that was a ZFS read parameter… In this post, we will take a look in another one, with the same “water to wine” effect. This time with focus on writes… We have a set of informations available for our [...]
Ganglia on OpenSolaris
As system administrators we need to have some essential info about our servers as a minimum requirement for our job, and identify patterns and obtain knowledge about trends in our workload. And, when we need to use Dtrace, MDB, or need to understand a FMA ereport… we do not have much time. Actually, i want [...]
Arithmetic exception
Ok, if you are a noob C programmer, you will find this post really fun, serious, it will make you LOL. If you are a noob, really noob “XYZ” programmer, maybe you find it helpfull… maybe… no. You will LOL too… So, one more time we have a core file sitting around on our servers. [...]
Do you need L2ARC redundancy? I do…
Hello there… I think you agree that the storage’s problem is the READ requests, synchronous by nature. And, as i said many times before, i think the solution for all problems (the answer for all questions ;-) is cache. Many levels, many flavors. I did read many times about the recommended redundancy on the ZFS [...]
Performance
These days i was working to understand a workload: random, many small files (e.g: web servers), running on NFS/ZFS environment. Interesting to see that the discs were really busy, a very heavy random workload, but a few NFS reads and writes requests. On top of it, an idle SSD as a ZFS Pool cache device. [...]
ZFS Internals (part #10)
PLEASE BE AWARE THAT ANY INFORMATION YOU MAY FIND HERE MAY BE INACCURATE, AND COULD INCLUDE TECHNICAL INACCURACIES, TYPOGRAPHICAL ERRORS, AND EVEN SPELLING ERRORS. From the MANUAL page: The zdb command is used by support engineers to diagnose failures and gather statistics. Since the ZFS file system is always consistent on disk and is self-repairing, [...]
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