Re: RAID controllers for Postgresql on large setups
От | Francisco Reyes |
---|---|
Тема | Re: RAID controllers for Postgresql on large setups |
Дата | |
Msg-id | cone.1210680025.806890.27271.1000@zoraida.natserv.net обсуждение исходный текст |
Ответ на | RAID controllers for Postgresql on large setups (Francisco Reyes <lists@stringsutils.com>) |
Ответы |
Re: RAID controllers for Postgresql on large setups
("Merlin Moncure" <mmoncure@gmail.com>)
Re: RAID controllers for Postgresql on large setups (PFC <lists@peufeu.com>) |
Список | pgsql-performance |
PFC writes: > You say that like you don't mind having PCI in a server whose job is to > perform massive query over large data sets. I am in my 4th week at a new job. Trying to figure what I am working with. From what I see I will likely get as much improvement from new hardware as from re-doing some of the database design. Can't get everything done at once, not to mention I have to redo one machine sooner rather than later so I need to prioritize. >In fact for bulk IO a box with 2 SATA drives would be just as fast as > your monster RAID, lol. I am working on setting up a standard test based on the type of operations that the company does. This will give me a beter idea. Specially I will work with the developers to make sure the queries I create for the benchmark are representative of the workload. >Adding more drives will help random reads/writes but do nothing for > throughput since the tiny PCI pipe is choking. Understood, but right now I have to use the hardware they already have. Just trying to make the most of it. I believe another server is due in some months so then I can better plan. In your opinion if we get a new machine with PCI-e, at how many spindles will the SCSI random access superiority start to be less notable? Specially given the low number of connections we usually have running against these machines. >If you mean doing large COPY or inserting/updating lots of rows using one > SQL statement, you are going to need disk bandwidth. We are using one single SQL statement. > http://tweakers.net/reviews/557/17/comparison-of-nine-serial-ata-raid-5-adapters-pagina-17.html I have heard great stories about Areca controllers. That is definitely one in my list to research and consider. > However RAID5 will choke and burn on small random writes, which will come > from UPDATing random rows in a large table, updating indexes, etc. Since > you are doing this apparently, RAID5 is therefore NOT advised ! I thought I read a while back in this list that as the number of drives increased that RAID 5 was less bad. Say an external enclosure with 20+ drives. >Have you considered Bizgres ? Yes. In my todo list, to check it further. I have also considered Greenplums may DB offering that has clustering, but when I initially mentioned it there was some reluctance because of cost. Also will look into Enterprise DB. Right now I am trying to learn usage patterns, what DBs need to be re-designed and what hardware I have to work with. Not to mention learning what all these tables are. Also need to make time to research/get a good ER-diagram tool and document all these DBs. :(
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