Re: Huge Data sets, simple queries
От | PFC |
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Тема | Re: Huge Data sets, simple queries |
Дата | |
Msg-id | op.s39morhucigqcu@apollo13 обсуждение исходный текст |
Ответ на | Re: Huge Data sets, simple queries ("Luke Lonergan" <llonergan@greenplum.com>) |
Ответы |
Re: Huge Data sets, simple queries
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Список | pgsql-performance |
>> Linux does balanced reads on software >> mirrors. I'm not sure why you think this can't improve bandwidth. It >> does improve streaming bandwidth as long as the platter STR is more than >> the bus STR. > > ... Prove it. > (I have a software RAID1 on this desktop machine) It's a lot faster than a single disk for random reads when more than 1 thread hits the disk, because it distributes reads to both disks. Thus, applications start faster, and the machine is more reactive even when the disk is thrashing. Cron starting a "updatedb" is less painful. It's cool for desktop use (and of course it's more reliable). However large reads (dd-style) are just the same speed as 1 drive. I guess you'd need a humongous readahead in order to read from both disks.
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