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Archive for March, 2007

Databases, cages and RAID-10, oh my!

Wednesday, March 21st, 2007
Posted in Storage Interconnects & RAID, Advisor - Tom Treadway

Question to the Storage Advisors: We’re buying 2 cages that use a PCIe interface and 24 146G 15K drives. We’re going to use RAID 10. Each cage only holds 12 drives. We’ll be using 2 spares in each cage. So that’s a stripe of 5 disk groups. At 175 IOPs that’s approx 875 IOPs across the stripe. If we go higher than 875 IOPs we begin seeing higher queue lengths correct? Both cages are hooked to the same server thru the PCIe controller that supports up to 8Gb/s. This is for an Oracle db, and will host 4 dbs. 2 dbs are IO intensive, 2 are not. Right now we plan on separating the 2 IO intensive dbs to 1 cage each. Would it be better to use both cages per db? I don’t think you can stripe disks across cages(?), so would it be better to create two stripes and put datafiles from both dbs on both cages so that we effectively use 2 stripes of 5 disk groups?

Fun with Disk Monitor

Tuesday, March 20th, 2007
Posted in Storage Interconnects & RAID, Advisor - Tom Treadway

Question to the Storage Advisors: How many disk IOs does it take to write one file? I have a RAID10 array writing a 120KB file. Is this one IO for the entire file, or is it one IO per sector on the disk/write cache (which would then be approx 240 IOs)?…

Bottlenecks: From disk to backbone

Tuesday, March 20th, 2007
Posted in Storage Interconnects & RAID, Advisor - Tom Treadway

Question to the Storage Advisors: I just wonder, what kind of storage solution that can saturate 10Gb Ethernet backbone. If I assume I have a file server (of course equipped with 10GbE NIC on PCI-E 8x), can an external SAS/SATA-II JBOD box (using 4xwide SAS link) produce enough throughput (taking into account the hard disk speed and the link bandwidth) to saturate the network? If not, where will be the bottleneck?…

SATA IOPS Measurement

Tuesday, March 20th, 2007
Posted in Storage Interconnects & RAID, Advisor - Tom Treadway

Question to the Storage Advisors: I’ve heard great things about SATA based DASD and JBOD devicess. I’ve found tons of information about the data transfer rate, but haven’t been able to find any hard data on how many sustained and bursted IOPS such systems can handle…

SATA vs SCSI?

Monday, March 19th, 2007
Posted in Storage Interconnects & RAID, Advisor - Tom Treadway

Question to the Storage Advisors: For network storage which is better: SATA 150 or SCSI ultra360. Balance size cost and speed. We need a terabyte for live data running and storage…