--- title: Hard drive Inner or Outer. What is Faster? description: This blog post explains why the location of the data isn't as important as a distance HDD head should make to access it. --- [Blog | Pythian ](https://www.pythian.com/blog) # [Hard drive Inner or Outer. What is Faster?](https://www.pythian.com/blog/hard-drive-inner-or-outer) Written by [Yury Velikanov](https://www.pythian.com/blog/author/yury-velikanov) | Jun 12, 2013 4:00:00 AM To be precise, I wonder if *OUTERmost *tracks of a spinning HDD are faster than *INNERmost* tracks. Should we put physical IO performance secretive data to *OUTERmost* parts of the disk and less critical data to *INNERmost* * *parts as several vendors suggests? Well I couldn't find a better solution than grabbing all HDDs I have and **start testing** :) ## Disclaimer Before you start criticizing my testing results I would like to make a few points clear: - I am not an expert in the hardware space. - I am just a curious Oracle Administrator, open to any suggestions on how to improve testing results and get closer to clarifying things. - Some of you will say that it is a useless exercise because we don't have any control over what areas of a single HDD data is placed nowadays. - Well, in some *rare* configurations like *Exadata* or *Oracle Database Appliance,* we actually have this power and can possibly impact the IO performance. - In other cases, it may be helpful to understand how things works to explain why there is a certain performance impact. - As I am an Oracle DBA and Oracle databases most often are random IO bounded, I have focused my attention on random (8k) IO testing. - I do believe there are better ways to test HDDs. Unfortunately, I don't have enough knowledge about other options. I am open to your suggestions on how to do it in a better way. - Just keep in mind that I have Windows 7 (64 bit), Dell Latitude E6410 for this testing. - At the moment, I am waiting on *SATA* adapter to arrive. I will re-run some of the tests I did to confirm or adjust the testing results. - This is a work in progress project, and I am not ready to make final conclusions ( if will be ready to make those at all ;) ) ## My expectations Based on previous experiences, I expect that: 1. *OUTERmost *tracks will not be much faster than *INNERmost* tracks. 2. The worst performance should be when data is accessed from both *OUTERmost *and *INNERmost* tracks **at the same time** I have focused my attention on 3 tests: - Data on* OUTERmost *tracks - Data on *INNERmost* tracks - Data distributed equally through full HDD surface Note: I have made a fourth test where I run random IO test accessing data from *OUTERmost *and *INNERmost* tracks at the same time. The test results were very close to the *full* surface tests. Therefore I do not provide those in this blog post. ## How and what did I test ### Hardware To start, I took 7 HDDs that I happened to have and 2 SATA to USB adapters. ### Software I have used 2 options to test and confirm IOPS results: - Windows 7 has a nice little (; silly ;) utility *[winsat](https://technet.microsoft.com/en-us/library/cc742157(v=ws.10).aspx)*. It didn't take me too long to figure out how to make it do random 8k reads. > ``` > winsat disk -ran -ransize 8192 -read -drive E > ``` - Oracle 11GR2 comes with the Oracle-native *orion* ([ORacle IO Numbers](https://lmgtfy.com/?q=ORacle+IO+Numbers)) utility. I just installed it and used the command below to test random IOs. > ``` > orion -testname e_hdd -duration 20 -cache_size 0 -write 0 -num_disks 1 -run advanced -size_small 8 -matrix row -num_large 0 > # e_hdd.lun > \\.\e: > ``` ### Assumption To make things simple I have assumed that HDD controller (Or Windows, or whoever... Remember that I am not an expert!) allocates space starting from *OUTERmost (fastest) *tracks of the disk. Therefore, I have allocated 1GB of *unformatted* space to *E:* drive first, then filled all space but the last 1GB with an empty partition and created a 1GB *G:* drive. My assumption is that partition/drive *E:* is located on *OUTERmost*on tracks but partition/drive *G:* on the *INNERmost* (slowest) tracks. As you will see from the results below, this assumption isn't correct for all HDDs.   To test full surface, I have deleted all partitions and created one big partition. Please let me know in the comment section below if there is a better way to ensure that a partition is created on *OUTERmost* tracks of HDD or at least how to check what tracks the partition is created on (if it is possible). ## Results ### "Good" results The following reflects IOPS testing for 3 HDDs that confirmed my expectations. It is clear that there is no less than 10% gain between *OUTERmost *and *INNERmost* tracks. However there is a significant performance impact if a HDD's head should move across whole HDD surface to access data. | **HDD Name** | **Outer** | **Inner** | **Full** | **Outer vs Inner** | **Outer vs Full** | | --- | --- | --- | --- | --- | --- | | WD 2.5" 1TB 5400RPM / WDBBEP0010BRD | 127 | 121 | 64 | 4.96% | 98.44% | | Hitachi 3.5" 320GB 7200RPM / HDT725032VLA380 | 133 | 124 | 58 | 7.26% | 129.31% | | WD 2.5" 160 GB 5400RPM / WD1600BEVT | 112 | 103 | 61 | 8.74% | 83.61% | ### "Other" results A careful reader would notice that I didn't provide all test results so far, and you are right. The reason is that the rest of the results don't confirm my theory :). Have a look on the other 3 HDDs test results below (Note that one of the 7 HDDs has data on it. Therefore, I have excluded it from *OUTERmost *and *INNERmost* tracks testing). | **HDD Name** | **Outer** | **Inner** | **Full** | **Outer vs Inner** | **Outer vs Full** | | --- | --- | --- | --- | --- | --- | | HGST 2.5'' 1TB 7200RPM / AT-0J22423 | 107 | 132 | 69 | -18.94% | 55.07% | | Segate 2.5'' 250GB 7200RPM / ST9250410AS | 88 | 71 | 63 | 23.94% | 39.68% | | Seagate 3.5" 1TB 7200RPM / ST31000333AS | 141 | 92 | 69 | 53.26% | 104.35% |   Either the 3 HDDs above showed results that I can't explain ( *AT-0J22423*) as of now or performance difference between *OUTERmost *and *INNERmost* tracks is more significant than for the first set of HDDs. However, it is somewhat clear that in both sets, there is a significant performance penalty if a HDD moves head across the whole surface. Those are expected result, aren't they? ## Intermediate conclusions There are some HDD models in which is no significant performance difference between accessing data located on *OUTERmost *or *INNERmost* tracks. However, in some cases, IO performance could be 130% slower if HDD header travels across the whole surface to return data. This has 2 possible practical implications: - If someone states that a partition is created on a *OUTERmost* tracks of a HDD, it doesn't necessarily mean that IO are significantly faster from that partition than from any other region of the HDD. - It could significantly slowdown IO operations if data were accessed from both *OUTERmost *and* *INNERmost* *tracks (e.g. if DATA is located on *OUTERmost *tracks but FRA on* ***INNERmost* *tracks). - You may find that your storage performance degrades more "active" data you put on your hard drives (fill hard drives). Keep in mind that there are possible exceptions. Based on my initial tests, there are some HDD models in which the difference between *OUTERmost *and * *INNERmost* *tracks is significant. ## Please help improve the test results As I stated at the begging of this post: a) I am not an expert in this space, b) This is a work in progress project and I am looking for better ways to test random IOs, and c) I need your help to understand why there are exceptions and need suggestions on how to adjust the HDDs testing process to improve the test results and get closer to good conclusions. Yury ## Database Consulting Services Ready to optimize your Oracle Database for the future?   [View full post](https://www.pythian.com/blog/hard-drive-inner-or-outer) ```json { "@context" : "http://schema.org", "@type" : "BlogPosting", "author" : { "@type" : "Person", "name" : "Yury Velikanov" }, "dateModified" : "2026-03-01T00:19:15.687Z", "datePublished" : "2013-06-12T04:00:00Z", "headline" : "Hard Drive: Inner or Outer?", "image" : { "@type" : "ImageObject", "height" : 60, "url" : "/hs/hsstatic/content_shared_assets/static-1.4092/img/default-amp-logo.png", "width" : 60 }, "mainEntityOfPage" : "https://www.pythian.com/blog/hard-drive-inner-or-outer", "publisher" : { "@type" : "Organization", "logo" : { "@type" : "ImageObject", "height" : 60, "url" : "/hs/hsstatic/content_shared_assets/static-1.4092/img/default-amp-logo.png", "width" : 60 }, "name" : "Pythian Blog" } } ```