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bpdski
Starting Member
3 Posts |
 Posted - 2007-06-15 : 12:08:21
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| Hi everyone, I'm trying to decide how to partition a new server machine that will have 8 SCSI drives in it. This machine is a quad-cpu box with 16Gig of RAM, so we shouldn't have paging issues.I've read a lot of opinions on how to do this, but what I'd like to find is real benchmarks where someone has tested different scenarios to figure out what works best for an OLTP application.A common opinion is to separate your O/S, data & log files all onto different spindles. This would lead you to setup a 2 drive RAID1 for OS, a 4 drive RAID10 for data, and a 2 drive RAID1 for log. However, a server with 16Gig of RAM will have little O/S activity once the machine boots up, so I think it's a waste to dedicate 2 drives to the O/S. Another idea is to create a 2 drive RAID1 array with 2 partitions for O/S and Log and a 6 drive RAID10 array for data. My final idea is to partition all 8 drives into a big RAID10 with separate partitions. Can anyone point me to some real benchmark tests that compare these setups? I would try to do my own, but I don't have physical access to the machine to do this. All of our hardware is leased and setup by our hosting center, we simply tell them how we want it configured.Thanks,Brian |
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eyechart
Master Smack Fu Yak Hacker
3575 Posts |
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bpdski
Starting Member
3 Posts |
Posted - 2007-06-18 : 07:45:56
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| Thanks for the link, that's a good writeup. It looks like I need to create a 2 disk RAID 1 for the logs, so I'll create a RAID 10 with the remaining 6 disks for the data and OS. |
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Kristen
Test
22859 Posts |
Posted - 2007-06-18 : 10:27:27
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I don't know diddly-squat about hardware, but:"RAID1 array with 2 partitions for O/S and Log"makes me think: the Log should be sequentially written, and thus ideally the heads should not move about randomly, therefore combining O/S and Log may not be a good better idea?We use 3 spindles (O/S, Data, Log) and my understanding is that ideally we should have 2 more spindles (for Backup and TempDB).We cross-store Backups onto the opposite spindle (Full backup -> Log spindle, Log backup -> Data spindle) to increase our chances of recovery if we have a failure on either spindle [if you like that idea it may influence how much capacity you need on each spindle]We use RAID10 for all spindles (dunno if that's good or bad compare to RAID1).We used to use RAID5 for Data, and every-time a drive went down it took the database with it  , so the Redundancy didn't exist in practice (at least not using the kit that we were for RAID5, but researching it: it did seem quite common for RAID5 - a drive failure during a write cycle will abort the write, rather than complete it on the remaining drives, possibly with no indication to the Application/User )Kristen |
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bpdski
Starting Member
3 Posts |
Posted - 2007-06-18 : 16:01:33
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| Thanks for the help Kristen. My thoughts on combining the OS and log drive are just that the OS should rarely access the hard drive once the machine is booted up. So, I wanted to maximize my performance on the data files. |
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RAID partitioning question