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IOPS calculation for SAN Design
Hi, we want to establish a SAN in near future and therefore we
calculate the technical basics at the moment. First of all we are interested in disk performance, particularly with regard to iops and throughput. The capacity planer from VMware delivers the average values of PhysicalDisk\trans, PhysicalDisk\Bytes/s per server and overall. According to these results, we have only a few iops (peak load 162) with 20 servers. In this analysis I have no declaration of the peak value per server, so I tried to find it out with the Microsoft perfmon. Here I get some strange values. I logged the disk performance with perfmon during one day. Perfmon shows a peak value of PhysicalDisk\trans/s of over 2000 (iops) at a server witch two SATA disks (Raid-1). The technical datasheet of these disks contain a typical value of 85 iops. Can this be true? How can I get realistic peak values of really existing iops to make a realistic design? Thanks for help, Holger |
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IOPS calculation for SAN Design
DataMover for Linux and Windows will provide this data for you. The
application performs an automated performance test across 14 different tranfer sizes and records throughput and IOPS for each transfer size along with standard deviation values for each of these data points. Contact the Moojit for a 30 day evaluation license. www.moojit.net wrote in message ups.com... Hi, we want to establish a SAN in near future and therefore we calculate the technical basics at the moment. First of all we are interested in disk performance, particularly with regard to iops and throughput. The capacity planer from VMware delivers the average values of PhysicalDisk\trans, PhysicalDisk\Bytes/s per server and overall. According to these results, we have only a few iops (peak load 162) with 20 servers. In this analysis I have no declaration of the peak value per server, so I tried to find it out with the Microsoft perfmon. Here I get some strange values. I logged the disk performance with perfmon during one day. Perfmon shows a peak value of PhysicalDisk\trans/s of over 2000 (iops) at a server witch two SATA disks (Raid-1). The technical datasheet of these disks contain a typical value of 85 iops. Can this be true? How can I get realistic peak values of really existing iops to make a realistic design? Thanks for help, Holger |
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IOPS calculation for SAN Design
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IOPS calculation for SAN Design
On 6 oct, 08:03, wrote:
Hi, we want to establish a SAN in near future and therefore we calculate the technical basics at the moment. First of all we are interested in disk performance, particularly with regard to iops and throughput. The capacity planer from VMware delivers the average values of PhysicalDisk\trans, PhysicalDisk\Bytes/s per server and overall. According to these results, we have only a few iops (peak load 162) with 20 servers. In this analysis I have no declaration of the peak value per server, so I tried to find it out with the Microsoft perfmon. Here I get some strange values. I logged the disk performance with perfmon during one day. Perfmon shows a peak value of PhysicalDisk\trans/s of over 2000 (iops) at a server witch two SATA disks (Raid-1). The technical datasheet of these disks contain a typical value of 85 iops. Can this be true? How can I get realistic peak values of really existing iops to make a realistic design? Thanks for help, Holger Hi Holger, First, and it's a rule, create your sizing at 70% of you peak, that's mean, if you have 2000 IOPS in your peak IO you must to configure your storage thinking in 2860 IOPS because it's a rule of the thumb, so, how many disks you need, depends, First you must consider, a physical disk can operate in average between 130 and 150 IOPS per disk, so, if you have 2860 IOPS you must to install 22 HDD aprox. and then you can obtain this 2860 IOPS. and depends of RAID level that you're using is the USABLE space that you can obtain, so here's another variable, cost per transaction. becuase if you are using RAID 5 you obtain more USABLE space than RAID 1+0. I hope that's information is useful for your. regards. |
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IOPS calculation for SAN Design
Don't under estimate the value of cache. I believe if you have an intelligent raid controller using cache effectively you're backend disks won't need to meet the peak iops you measured in many situations. For example, are the 2000 iops a mixture of reads and writes. Read cache hits would require no physical disk operation. I have seen a hitachi 9980 serving storage for a multi terabyte transaction processing database maintain a very good cache hit rate. Also, when a raid controller has write cache it can stage writes to physical media efficiently so that 2000 iops from the host's view would result in something potentially much smaller on the array's backend disks. Regards, Vic On Oct 18, 9:58 pm, alexup wrote: On 6 oct, 08:03, wrote: Hi, we want to establish a SAN in near future and therefore we calculate the technical basics at the moment. First of all we are interested in disk performance, particularly with regard to iops and throughput. The capacity planer from VMware delivers the average values of PhysicalDisk\trans, PhysicalDisk\Bytes/s per server and overall. According to these results, we have only a few iops (peak load 162) with 20 servers. In this analysis I have no declaration of the peak value per server, so I tried to find it out with the Microsoft perfmon. Here I get some strange values. I logged the disk performance with perfmon during one day. Perfmon shows a peak value of PhysicalDisk\trans/s of over 2000 (iops) at a server witch two SATA disks (Raid-1). The technical datasheet of these disks contain a typical value of 85 iops. Can this be true? How can I get realistic peak values of really existing iops to make a realistic design? Thanks for help, Holger Hi Holger, First, and it's a rule, create your sizing at 70% of you peak, that's mean, if you have 2000 IOPS in your peak IO you must to configure your storage thinking in 2860 IOPS because it's a rule of the thumb, so, how many disks you need, depends, First you must consider, a physical disk can operate in average between 130 and 150 IOPS per disk, so, if you have 2860 IOPS you must to install 22 HDD aprox. and then you can obtain this 2860 IOPS. and depends of RAID level that you're using is the USABLE space that you can obtain, so here's another variable, cost per transaction. becuase if you are using RAID 5 you obtain more USABLE space than RAID 1+0. I hope that's information is useful for your. regards. |
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