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  1. O

    Confused about ZFS performance on SSD

    I actually think that the low write rate of the Samsung consumer SSDs is a rather good sign for the firmware implementation of the drives. When a cheap consumer class SSD like the Kingston v300 or the Intel 535 can achieve such a high sustained random 4K performance I get skeptical. Such a...
  2. O

    X10SL7-F SAS to RES2SV240 Expander to Backplane not working

    I use that exact setup, so I definitely know it works. And you won't need the sideband, as the sideband info will be transmitted in-band from the controller to the expander. The sideband is required if you connect the backplane directly to the controller and want to control the LEDs.
  3. O

    samsung 840 pro 256GB not recognized any longer

    Any component in your computer can fail at any time. That is why you backup your data.
  4. O

    850 Evo M.2 vs 2.5" and other questions

    Yes, exactly. Retail version with 3D V-NAND like in the 850 series drives.
  5. O

    Need help PC crashes and SSD disappears on and off.

    Not so quick. SATA power connectors are crap for everything but backplanes. I guess the power is to blame as least as often as the SATA cable.
  6. O

    ZFS Performance Issues

    dd is not a benchmark. You have no control over syncs and queue depths. There is a post from me in this subforum how to use fio to properly benchmark sequential write speed. Are you sure you should get more an an encrypted block device? The processor is somewhat old and does not have hardware...
  7. O

    WD Caviar Green - Reliability?

    Usually all drives 7200rpm and higher will exceed proper operating conditions (~50°C) without active cooling. There are a few exceptions, notably cases where they are screwed to more solid metal parts.
  8. O

    Platter HDD is SLOW, but bursts fast

    Check the SMART data with CrystalDiskInfo. The drive could to be at the verge to death.
  9. O

    Open Indiana rpool full

    How can proc be using space? It is a virtual filesystem not located on disk. Unless Solaris/OpenIndiana works completely different than any *nix I ever used. please post the output of zfs list -r -t all rpool and du -h -x -d 1 / (note that I use mainly Linux and do not know whether the...
  10. O

    Cheapest PCIe M.2 Storage?

    The M.2 850 EVO is a SATA drive, it will not work in a PCIe-only slot. Your options are Plextor M6e, Samsung XP941, Samsung SM951 and the HyperX Predator. All three are good with the SM951 as the fastest.
  11. O

    Physical HDD/SSD Cloning device

    I'm not sure something like that exists. There are some copy stations around, but you would need something that is filesystem-aware. I do not know of a single one that is. My solution to your problem would be a well scripted/automated PC with some hotswap trays. Resizing filesystems with bad...
  12. O

    LSI and Cachecade Pro

    A single fast PCIe SSD like the Intel P3700 will blow any caching solution out of the water. If you need redundancy buy two and make a RAID1. Caching only makes sense if the footprint of the workload fits on the SSD cache.
  13. O

    Any BX100 owners here?

    This drive has not been around long enough to make such assessment. I personally considered them as "storage" SSD for my server, but 850 EVO has much better burst and random read performance for almost the same price. Is there a reason to replace the 840 EVO? If you do it because of the read...
  14. O

    what's the highest quality Western Digital hard drive?

    The MTBF values are too similar to be based on actual failure rates. Maybe they calculate them based on the failure rates of the individual parts. A a simple mistake in the firmware can destroy a drive much faster.
  15. O

    Ruining TLC Reputation

    The 840 EVO still has one of the best price/GB ratios around. Samsung drives seem to are very resilient against sudden power loss. I had to replace a MX100 in a specific laptop that often had filesystem corruption or bluescreens after suspend-to-disk. Since I replaced the drive by an 840 EVO...
  16. O

    what's the highest quality Western Digital hard drive?

    How they are specified and rated can be read in various datasheets and press releases. What I mean are actual technical differences, which are not published. You would either have to talk with the engineers or open the drives yourself. Patrick seemed to have some insight.
  17. O

    what's the highest quality Western Digital hard drive?

    Do you know how the RED Pro and Se drives compare to the Black and RE4 mechanically?
  18. O

    2x240GB SSD in Raid 0 = Gaming performance?

    Following this logic you cannot buy Intel, Samsung, Crucial and OCZ. All of these had problems with SSDs, some were rather devastating (Intel 8MB bug, Crucial m400 bricks, several types of OCZ drives).
  19. O

    Storage configuration for two small All-In-One ESXi boxes

    The twisted pair drivers consume significantly more power than DAC transceivers. If it is for point to point and short range the X520 is preferrable. If it is for a bit longer range and you can use fibre and can get the SFP+ modules cheap on ebay it is even better.
  20. O

    what's the highest quality Western Digital hard drive?

    If you had three drives die in the same spot there is a high chance that the reason is something else.
  21. O

    Why is my MX200 doing this?

    It is a budget drive, although one of the better. The price is comparable to the 840/850 EVO and MX100 drives. If you look at the better drives like Intel 730 or Samsung 840/850 Pro, those are 50% more expensive.
  22. O

    what's the highest quality Western Digital hard drive?

    There are also SATA versions of the WD RE4, which in hardware are very close to the WD Black.
  23. O

    Why is my MX200 doing this?

    I cannot comment on the MX200, but this behaviour is observable on a lot of budget SSDs. The sector ranges that contain actual data have a much slower read speed than the empty (and TRIMmed) space, which basically reads at line speed. I have seen this on the MX100 as well. I could not observe...
  24. O

    Intel SRT limited to one cache?

    It is just a cheap consumer solution. Just like Samsung RAPID, which is limited to a single SSD as well.
  25. O

    SATA III SSD in RAID 0 vs. NVMe ?

    The LSI RAID controllers are not cheap, if you are willing to spend that much it would be better to not go the RAID route and use an NVMe drive. The Intel P3x00 series are a good recommendation depending on the required write speed. The Samsung EVO drives are not a good choice for that type of...
  26. O

    LSI 9260-8i + Sleep = Rebuild?

    I doubt that the driver gets properly tested for things like sleep mode even if the basic support is genrally there. Server hardware not running = no revenue, so this is a feature that not many people will actually use.
  27. O

    Using RAID-5 Means The Sky Is Falling

    I have been using Linux mdraid for almost 15 years now and basically used external checksums for media files (CRC32) since the beginning. I never encountered a single corrupted file on a software RAID5/6. There have been many unreadable sectors on disks, but since the disk does not read such...
  28. O

    M.2 and SSD's 20 to 40 Gbps with NVMe

    I don't think you can do bait-and-switch tactics for OEM-only products, at least not without major consequences for future contracts. The companies that will buy these SSDs will be well aware of the specs. Or do they plan do make these SSDs a retail product after all? At least the name does not...
  29. O

    ZFS dedupe is fixed soon

    Since you like quotes and references so much more than logical reasoning, there is a link on this site to a post "Real world data deduplication savings under Windows 2012" where you can read:
  30. O

    WD® Delivers World's Most Power-Efficient High-Capacity 3.5" HDD For Modern Datacente

    So the good news is that we now have enterprise grade 5X00 rpm drives. I hope that they come with the lower noise and power consumption of 5X00 rpm drives and not only with the lower performance.
  31. O

    ZFS dedupe is fixed soon

    While the math is wrong the validity of the argument remains. Highly compressed video really behaves like noise. It is impossible to deduplicate. Even when it is lossless, good lossless compression is similar to noise as well. We should not forget that lossless compression already is...
  32. O

    ZFS dedupe is fixed soon

    This formula describes permutations without repetition. We can agree that the same byte can be used multiple times in a 128 KiB block. So r^n would be the formula to use.
  33. O

    ZFS dedupe is fixed soon

    I agree with his other arguments, but this number seems wrong. There are 256^(128*1024) possible permutations of a 128K block. This is roughly 10^315000, number with 315000 digits. Note that the universe is estimated to comprise 10^80 protons.
  34. O

    ZFS dedupe is fixed soon

    These are two conflicting mechanics, dedup works well with small block sizes while compression is better with larger blocks. To make effective use of dedup the NTFS cluster size (4k by default) should be at least as large as the ZFS volume block size (8k by default).
  35. O

    ZFS dedupe is fixed soon

    I did actually try to determine the space savings of my 12 GB media library with zdb. The deduplication space saving ratio was less than 1 percent. If you approach even 2x with dedup, it is because of large duplicate files, which can be taken care of by much simpler means - SnapRaid does it for...
  36. O

    High availability storage using SAS expanders

    But this only works with SAS disks, right? Do SATA disks also work with multiple HBAs?
  37. O

    Point-to-point FibreChannel

    What do you mean with "PCI-x but should work in PCI-e"? PCI-X and PCIe are not mechanically or electrically compatible. PCI-X may work in legacy PCI, however. FC does block level links, comparable to what iSCSI does. You cannot get normal network traffic across that link.
  38. O

    ZFS pool question

    Yes, the UDMA CRC errors are way to high for a single power loss and they probably still increase if you take the checksum errors into account. Check SATA cables, power cables and PSU. It could probably also be the controller or controller ports that have issues.
  39. O

    Samsung 840EVO Running at slower speed

    Magician reports an up to date firmware even if the restoration fix is not applied. The reason for that is probably that it cannot be applied by Magician but only by a separate tool.
  40. O

    ZFS pool question

    So many parallel distributed errors on a newly created pool? You should check the SMART data of the disks and your power supply. Maybe the sudden power loss damaged it - unlikely if it is a quality PSU, but I had a dead Seasonic PSU after a blackout some years ago.
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