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  3. The change in transfer rate looks right, the further you get on a spinning disk the fewer sectors travel under the heads in a given time, so the transfer rate decreases. It's a function of where you are reading from on the disk, not of temperature (unless of course you are overheating the disk-- but 44C is within operating spec, so that shouldn't be a factor).
  4. The WD Ultrastar DC HC520 / HGST He12 should have a transfer rate of 243MiB/sec. This is true for the first two TBs, but than it degrades to only 50% in the center of the drive. Used the following script to run 5 cycles. For each cycle measured the transfer rate at each start of a TB. #!/bin/bash for run in 1 2 3 4 5 do for i in 11 0 1 2 3 4 5 6 7 8 9 10 11 do echo "RUN=$run SKIP=$i" b=`expr 1024 \* 10`k s=`expr $i \* 100`KB c=`expr 1024 \* 1` dd if=/dev/sdg bs=$b iflag=direct skip=$s count=$c status=none | pv -b -t -r >/dev/null /usr/sbin/smartctl -a /dev/sdg | grep ^194 # show temperature echo done done Each cycle showed the same transfer rate (there was no variation) at a specific TB start, independent of temperature. SKIP=0 10.0GiB 0:00:42 [ 242MiB/s] SKIP=1 10.0GiB 0:00:42 [ 242MiB/s] SKIP=2 10.0GiB 0:00:43 [ 235MiB/s] SKIP=3 10.0GiB 0:00:45 [ 226MiB/s] SKIP=4 10.0GiB 0:00:46 [ 220MiB/s] SKIP=5 10.0GiB 0:00:48 [ 210MiB/s] SKIP=6 10.0GiB 0:00:50 [ 202MiB/s] SKIP=7 10.0GiB 0:00:53 [ 192MiB/s] SKIP=8 10.0GiB 0:00:57 [ 178MiB/s] SKIP=9 10.0GiB 0:01:01 [ 166MiB/s] SKIP=10 10.0GiB 0:01:08 [ 149MiB/s] SKIP=11 10.0GiB 0:01:18 [ 129MiB/s] RUN=1 33Celsius RUN=2 39Celsius RUN=3 42Celsius RUN=4 43Celsius RUN=5 44Celsius Did somebody else notice this 50% drop of transfer rate for these drives? Did you receive a sustainable transfer rate through the drive? Hope to have some users running my script and showing their results for similar drives.
  5. Kevin OBrien

    BIOS not showing my SSD M.2

    Could you clarify the problem? Does the system boot and work correctly? I can't tell if you are asking about why the drive isn't showing up, but still works and is seen by the OS and Kingston SSD manager, or if you are asking why it won't work in that notebook but it works in others. It looks like the BIOS sees it just fine in the boot order. Being a notebook, sometimes BIOS stuff gets quirky depending on how the OEM set it up.
  6. Kevin OBrien

    How is this Speed Possible?

    Was going to say the same thing. DRAM caching.
  7. I like the dedication, lol
  8. I have no idea how Android works or its file sizes etc. But I have a hard time believing that there's any perceived speed difference amongst any of the top branded cards.
  9. Brian

    Seagate Exos 7E8 vs 5E8

    We just gave away two of those Archive 8TB drives. Sloooooooow.
  10. I might be being dense, but what does this app do? I mean you could use virtualization to set up a VM and run it.
  11. Brian

    Portable USB HDD vs Powered HDD

    Functionally makes no difference. The portables are a little more simple I suppose in the event the power cables fail or someone wants to read the contents of the drive in a bank vault or something.
  12. Earlier
  13. continuum

    How is this Speed Possible?

    Do you have Samsung SSD Magician installed? If so it's probably reading from the system memory cache that Samsung SSD Magician supports.
  14. Getting crazy fast benchmarks on my SSD drive..what is going on?
  15. continuum

    Portable USB HDD vs Powered HDD

    Uh, doesn't really matter? 2.5" bus-powered disks are usually more shock resistant than their 3.5" desktop counterparts, if that helps your decision any.
  16. I dont know the reason why my SSD is shown as NOT installed. I am using a Win 10 64 bit OS I have a Kingston SSD M.2 that is my main drive where the OS is installed I have updated all my drivers and SSD firmware. My Kingston SSD manager recognizes the SSD https://ibb.co/qrSKMg3 https://ibb.co/FqkNTJn https://ibb.co/9GYmw2D https://ibb.co/vqwsWxH
  17. Hi All, I need to save 4 TB of my family photos + videos onto two HDDs. I have the following options 1. Use two 4TB WD 4TB Elements Desktop Hard Drive - USB 3.0 - WDBWLG0040HBK-NESN (These are powered with an external adaptor) I plan to use two such HDDs so I have a spare if one fails 2. WD 4TB Elements Portable External Hard Drive - USB 3.0 - WDBU6Y0040BBK-WESN (Non Powered only via USB) I can use two of these to save all data 3. Use 1 Hard disk 4 TB (Powered with adaptor) and a 2nd HDD (4 TB Powered with USB) Please advise. -thads
  18. continuum

    Seagate Exos 7E8 vs 5E8

    ST8000NM0055 is the superior drive, there's no reason to pick up a SMR drive like the ST8000AS0003.
  19. continuum

    Question about RAID5/6 and/or ZFS raidz1/2 theory

    Depends how many disks you want to mimick. Then use Brian's calculator above to determine your percentages.
  20. What is Relevant benchmark values for microSDcard performance for Android Mobile phones? I found benchmarks of micro SD card in various websites. For reading those values and deciding and understanding and clarifying which one is relevant for adoptable/ swapping. I want to know what speed value is relevant for Internal/External storage Online Websites and Andro benchmark app and gives values of Sequential read and write 1000 MB/s Random read and write 512KB Random read write QD1 4KB MB/ps Random read write QD32 4KB MB/ps Random read write QD1 4KB IOPS Random read write QD32 4KB IOPS For using my MicroSDcard as adaptable OR swapping storage **Now my questions are :-** 1. System booting Android applications **read and write randomly or sequentially** which values more relevant means application writes randomly or sequentially 2. What **Queue Depth QD** is relevant for Booting android system and basic applications **QD1 or QD32** 3. Which **Block size** android applications work in **4KB or 8KB 512 Bytes** block size on what ground it should be compared 4. what speed of **reading or writing** is more relevant for booting system and general application an adoptable swapping storage 5. what value should be compared OR more relevant **MBPS or IOPS** for QD1 4KB and QD32 4KB while considering applications writing or reading speed 6. what **RANGES OF VALUES** of following benchmarks criteria will be sufficient or believed excellent for booting and system application A Sequential Read 1000MB/s B Sequential Write 1000MB/s C Random Read 512 MB/s D Random Write 512MB/s E Random Read QD1 4KB MB/s F Random Write QD I 4KB MB/s G Random Read Qd32 4KB MB/s H Random Write Qd32 4KB MB/s I Random Read QD1 4KB IOPS J Random Write QD I 4KB IOPS K Random Read Qd32 4KB IOPS L Random Write Qd32 4KB IOPS **IN ADVANCE I APPRECIATE OBLIGE AND THANKFUL FOR GIVING YOUR PRECIOUS TIME AND EFFORTS FOR GIVING ANSWERS**
  21. Hi, I'd like to know some relevant differences between this drives besides MTBF. 7E8 model ST8000NM0055 (MTBF 2,000,000 hr) 5E8 model ST8000AS0003 (MTBF 800,000 hr) 5E8 model is formerly known as an Archive HDD, both are 8TB so obviously I want to use them for archiving purposes. 7E8 seems generally better choice, but everywhere I look 5E8 costs more than 7E8 which is quite confusing. Do you have an experience with this drives, and/or recommendations? Thanks!
  22. alpha754293

    Question about RAID5/6 and/or ZFS raidz1/2 theory

    So... What parameters should I be specifying for the par2 command line tool in order to calculate/generate the parity data that mimicks the more traditional RAID5/RAID6 configurations?
  23. Phanteks Enthoo 719 just came out, I'd say it's one of the few that supports that many drives at a non-crazy price. https://www.newegg.com/satin-black-phanteks-enthoo-luxe-2-full-tower/p/N82E16811854088 Looking at photos, the Corsair 900D might, but then you have power supply fitment limitations and a lack of cooling for some of the drives. Adapting the 5.25" bays to fit some 3.5" drives might alleviate the power supply fitment limitations... https://www.corsair.com/us/en/Categories/Products/Cases/Obsidian-Series™-900D-Super-Tower-Case/p/CC-9011022-WW
  24. continuum

    Question about RAID5/6 and/or ZFS raidz1/2 theory

    Correct. The goal is to still ensure uptime, not to prevent failed disks.
  25. alpha754293

    Question about RAID5/6 and/or ZFS raidz1/2 theory

    But that only just postpones/delays the same fundamental failure mode. You're just increasing the number of layers in order to statistically reduce the probability of the failure mode/error state from occurring. I mean, to that end, there is nothing that you can't have septuple parity as your probability of the failure mode occurring will drop to somewhere on the order of 10^-9 to 10^-16 or less. (I haven't done the math, so I'm guessing in regards to the order. If someone else who is smarter than I am can do the math, then I can update that.)
  26. alpha754293

    Question about RAID5/6 and/or ZFS raidz1/2 theory

    But how would you then label the tapes so that the data would be consistent? Wouldn't this mean that in order for the data and the parity to be consistent that you would only be able to write the data in (n-1) "chunks" - i.e. if you had 3 LTO-8 tape drives, the total raw, uncompressed capacity would be 36 TB, with only 24 TB that's "usable" since 12 TB would be used to store the parity data. That also means that those three tapes will always have to work in conjunction with each other, so when you want to read data from this group of tapes, you will have to load all three tapes into the three tape drives simultaneously in order for this to work, correct? And if you have 5 drives, then you would have to load all five tapes in at the same time for this to work, right? (etc. etc. as you increase the number of tape drives) Conversely, why do that when you can just use par2 instead? You write the parity data to each individual tape so that with a single drive, the tape will contain all of the information self-contained within the tape, and if you are worried, you can also create/write parity of the parity data onto the tape as well. Isn't that what double parity does? Single parity is parity on your original data/file. Double parity would be parity on top of your original data/file AND the first set of parity data that was generated/calculated by the RAID HBA or OS/CPU if you're using software RAID? And if you are worried about the tape being a single point of failure (e.g. the tape is burned up in a fire), you can have x number offsite, colocated copies for disaster recovery. This way, you don't have to wait for n number of tape drives to synchronize (and loading n number of tapes simultaneously) to be able to move data around. Instead of waiting to eject and load 5 tapes, while one tape is being ejected, another could already be loaded and it can start reading the next tape already. Whereas with RAIT, you'd have to synchronize the tape drives so that the group of tapes will work as a single unit together. (And the load/unload mechanism isn't exactly the fastest, even with LTO-8. It can still take upto a minute with my current drive (not a tape library) to bring a tape up online so that it can be read/written to.)
  27. continuum

    Question about RAID5/6 and/or ZFS raidz1/2 theory

    This is why RAID5 or RAIDZ is not recommend by many, and RAID6 or RAIDZ2 is preferred instead.
  28. Seriously? You necro a 11.5 year old thread to post a spam link to kitchenware?
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