SSD or USB Key?

  • Hi everyone.
    Since I'm planning to do a new installation with OMV4 over a different device (So in case of emergency I will keep my USB key with OMV3).
    My only doubt is: it's worth waiting for a 60GB SSD to drop around 25€, or I should by a good USB of 16/32GB like the Sandisk Ultra Flair for 10/16€?
    The disk size it's not the problem, my biggest issue is that with classic usb key you need plug-ins to avoid writing and you can't use smart commands, that's why I was thinking about a very cheap SSD

    Intel G4400 - Asrock H170M Pro4S - 8GB ram - Be Quiet Pure Power 11 400 CM - Nanoxia Deep Silence 4 - 6TB Seagate Ironwolf - RAIDZ1 3x10TB WD - OMV 5 - Proxmox Kernel

  • Look around on ebay. I can still find used 16GB Samsung 2.5 SSDs for ~20USD.

    --
    Google is your friend and Bob's your uncle!


    OMV AMD64 7.x on headless Chenbro NR12000 1U 1x 8m Quad Core E3-1220 3.1GHz 32GB ECC RAM.

  • well, the choice is easy:


    - SSD means one less sata connector. If you don't need it go for a small cheap SSD.
    - USB means one more sata connector, but the need to use the addon for booting on usb ( sorry, cant remember the name )

  • well, the choice is easy:


    - SSD means one less sata connector. If you don't need it go for a small cheap SSD.
    - USB means one more sata connector, but the need to use the addon for booting on usb ( sorry, cant remember the name )

    You missed one, the one I use. 16GB 2.5in SATA SSD in an external USB case.


    You were probably thinking of the Flash Memory plugin. Vital if OMV is on a USB thumbdrive or SD/CF card, but I use it anyway on my SSD.

    --
    Google is your friend and Bob's your uncle!


    OMV AMD64 7.x on headless Chenbro NR12000 1U 1x 8m Quad Core E3-1220 3.1GHz 32GB ECC RAM.

  • You missed one, the one I use. 16GB 2.5in SATA SSD in an external USB case.
    You were probably thinking of the Flash Memory plugin. Vital if OMV is on a USB thumbdrive or SD/CF card, but I use it anyway on my SSD.

    absolutly, coudnt remember the name and was thinking of internal SSD...

  • In Italy I can't find anything cheaper than 25€, sadlythere isn't any 16gb ssd on ebay here :(
    Still I thank you for the SSD inside a usb 3.0 case! It's a great idea and I'll probably go for it!

    Intel G4400 - Asrock H170M Pro4S - 8GB ram - Be Quiet Pure Power 11 400 CM - Nanoxia Deep Silence 4 - 6TB Seagate Ironwolf - RAIDZ1 3x10TB WD - OMV 5 - Proxmox Kernel

  • An SSD lasts a lot longer than a USB thumbdrive

    No. Both use flash cells so they suffer from the same problem and quality of components is not detemined by the product category.


    It's perfectly easy to buy a crappy (m)SATA SSD on Aliexpress or something off eBay that implements technology from a decade ago which will die way earlier compared to an industrial SLC USB thumbdrive. There is no magic involved, these are just different packages using different host interfaces and you have to look a little bit closer.


    There exist good quality consumer SSDs that will outlive yourself by decades but also crappy SSDs ('buy cheap, buy twice' -- this simple rule exists here too) that consist of some eMMC combined with an outdated controller not implementing TRIM and faking some of the SMART attributes (eg. temperature). Such an SSD can be a much worse buy compared to an USB pendrive. And then there exist counterfeit SSDs as well (just enter 'counterfeit SSDs' or eg. 'counterfeit EVO 850' in your search engine of choice)


    IMO it's pretty easy to deal with the problem:

    • always check for counterfeit flash media directly after purchase with either F3 or H2testw (also with SSDs especially if you're following the 'buy cheap, buy twice' route)
    • since chances are great that you got counterfeit stuff choose sales channels with a 'no questions asked' return/refund policy (especially never ever buy 'genuine flash' on places like Aliexpress, eBay and the like)
    • If you want to prevent your flash media wearing out too fast ensure that you are able to TRIM (here good/genuine SSDs win over USB pendrives, but even SD cards outperform USB pendrives here since they can be trimmed from time to time by sending CMD38/DISCARD)
    • ALWAYS use the flashmemory plugin with flash media and this applies to SSDs too (since especially when you bought a crappy one that fakes TRIM it will die way earlier than necessary without the plugin). Setting up a cronjob that syncs stuff back to 'disk' hourly or daily is a good idea since it still greatly reduces 'write amplification' while ensuring that if your OMV box should crash only small amounts of logs and metadata are lost

    BTW: people recommend sometimes SLC flash (more expensive USB pendrives). Fraudsters love this since it allows to sell cheap flash relabeled as SLC for much more money :)

  • 16GB 2.5in SATA SSD in an external USB case

    With a 16GB SSD it's most probably not an issue since this thing is too old anyway and doesn't support TRIM?


    But SSDs especially with small capacity should support TRIM since once the total amount of data written to the disk has exceeded the drive's capacity TRIM or not makes a huge difference wrt wearing out too fast or not. Without TRIM the SSD thinks all pages are used and now every new write or change request ends up using pages in the overprovisioning area and erasing whole erase blocks (the garbage collection and wear leveling processes are way more inefficient since they've to deal with data that is not used any more). This not only reduces performance (not that relevant with an OMV OS drive) but also greatly the lifetime. TRIM makes the real difference here.


    Does a SATA SSD inside a random USB disk enclosure support TRIM any more? Usually NOT.


    It would need to be a pretty new and UAS capable disk enclosure that also fully supports 'ATA passthrough' (the feature is called SAT 'SCSI / ATA translation') since if the USB controller is only capable of the old and boring Mass Storage protocol then there's no way to tell the SSD which areas are free. So you end up with an SSD crippled down to a dumb thumbdrive. It also needs a pretty recent Linux kernel for this to work since without driver support you also end up with no TRIM over USB (just one of the many many downsides of USB storage)


    The only real advantage then over a thumbdrive if you bought a quality SSD is that you might still use SMART to query the SSD about its remaining lifetime (good SSDs support at least one SMART attribute that internally calculates the wear out but this is vendor specific so you need to dig into details. And of course the cheap SSD crap you buy off Aliexpress or eBay does NOT support this feature so especially in an old USB disk enclosure these SSDs behave exactly like a pendrive). It's easy to test for both with 'hdparm -i' and 'smartctl -x' (though after purchase only ;) )


    Further reading: https://superuser.com/question…after-heavy-usage/1118809

  • Look around on ebay. I can still find used 16GB Samsung 2.5 SSDs for ~20USD

    Buying USED SSDs when it's about fearing flash storage wearing out too fast is a questionable attempt.


    All flash media has a write cycle limitation and all flash media will die once flash cells are worn out. A used SSD as the name says has obviously been already in use. You would need to know how much it is worn out already. More recent SSDs from renowned vendors provide this information through SMART (cheap and crappy SSDs usually don't or fake the returned value). Some information on this: https://unix.stackexchange.com…or-the-mediums-wear-level


    So if you buy a used SSD the seller would have to provide this information (ranging from 100 -- brand new -- to 0 which means 'worn out', counterfeit SSDs will show always 100 of course) since this is the only way to judge whether you buy something you can write still a lot to or that will die as soon as you wrote the next few GB to it. If the seller does not provide this information you're simply lost since it's perfectly possible that you get a used SSD that's already at the end of its life.


    So please stop treating product categories like 'SSD', 'USB thumbdrive' or 'SD card' as more than they are. They are different types of flash products differing wrt form factor, connector type and usable protocols. That's it. There is no quality or endurance expectation associated with any of these categories and the main problem with every flash memory product (counterfeit crap being sold as faked genuine products) applies to all three categories as well. For example:

    • A genuine SD card with nice random IO performance can be the better choice than a counterfeit or crappy SSD.
    • A genuine MLC flash USB thumb drive is the better choice than a counterfeit SLC fake (are you an engineer and can spot the difference in your lab? If not why are you trying to buy SLC then? The fraudsters trust in you spending more money on 'SLC flash products' so that's how they label their fakes).
    • A SATA SSD that is TRIM capable on a SATA port is something entirely different than the same SSD in a random USB enclosure (TRIM and SMART have to work and this requires a pretty recent/decent USB-to-SATA bridge in the enclosure and also a pretty recent kernel version since otherwise TRIM won't work even if the controller would support this

    To everyone asking himself how to deal with flash media (for an OMV boot drive): Replace trust and 'common knowledge' with control and real knowledge. And since problem N° 1 with flash memory products is 'fake flash' (also called counterfeit flash -- see this nice test here of 20 SD cards with rather large capacity back then of which 17 were fakes) the most important rules are

    • avoid sales channels that favour fraudsters over you. Always choose only sellers with a 'no questions asked' return/refund policy
    • check each and every flash product you buy directly after purchase with either F3 or H2testw
    • return the product if it has not full capacity or performance is too low
    • use the flashmemory plugin in OMV with each type of flash memory (SSDs, USB thumbdrives, SD and CF cards)
    • If you're still paranoid wrt flash media wearing out too fast buy larger capacities. If you need 8 GB for your OS drive (OMV needs not even this) then buy 64GB or even 128GB since these devices will wear out 8 or even 16 times later (but if you tested the card and use flashmemory plugin there's nothing to worry anyway). Don't buy 256GB or above especially when their price looks to good to be true since it's fake for sure (tons of clueless consumers even think USB thumbdrives with 2TB for less than 50 bucks are possible. But that's just one of the many reasons why you should never ever buy flash storage on eBay, Aliexpress or similar sites)
  • That being said I should add that we use for the OS install on all our OMV servers (and ESXi as well) solely USB thumbdrives or SD cards. The latter are genuine Samsung EVO or EVO+ or starting from now on SanDisk Ultra A1 (the A1 is important!). USB thumbdrives are also only from those vendors who produce their own NAND flash, their own controllers and assemble this on their own to retail products (since we hate fake flash and if a vendor controls the whole production process this is less likely to happen already at assembly stage).


    When buying any USB peripheral these days I would only buy stuff that's USB3 compliant (since then controllers inside are pretty recent and you avoid slow, outdated and buggy stuff). USB3.0/3.1 is not the same as '5 Gbps' and USB 3.2 is not the same as '10 Gbps'. USB3 is a protocol revision also indicating some capabilities and that the stuff is not horribly outdated. But those link data rates of '5 Gbps' or even '10 Gbps' are associated with transfer modes called SuperSpeed or SuperSpeed+.


    If possible we always try to avoid SuperSpeed for a couple of good reasons so yes, the recommendation for an USB thumbdrive where OMV should live on is buying an USB3 product and use it on an USB2 port (to ensure that SuperSpeed is NOT used avoiding a lot of hassles -- once USB-C is omnipresent that might change)

  • Thanks a lot for your help :) I totally forgot about TRIM commands, and also I didn't know that if I put an SSD with TRIM inside a USB 3.0 case I still risk to disable TRIM.
    So if I've understood well, you suggest micro SD over USB key right?
    Which Micro SD do you suggest between Sandisk ultra A1, extreme A1 and Samsung evo (not A1)? There is any way to find a TBW for micro SD like for SSD?

    Intel G4400 - Asrock H170M Pro4S - 8GB ram - Be Quiet Pure Power 11 400 CM - Nanoxia Deep Silence 4 - 6TB Seagate Ironwolf - RAIDZ1 3x10TB WD - OMV 5 - Proxmox Kernel

  • So if I've understood well, you suggest micro SD over USB key right?

    I prefer SD card over USB thumbdrive if I can for the simple reason that I consider being able to TRIM at least from time to time important.


    But I took the time for these lengthy replies in order to warn for some common misbeliefs since SSDs aren't always superiour especially not when it's about to buy used ones or put them into USB enclosures (my experiments here were rather discouraging, only with a pretty recent JMS578 chip with latest firmware I got TRIM to work. According to others ASM1351 should also allow for TRIM but all reports are based on Startech devices like this so maybe there's a custom firmware needed only Startech provides).


    Which Micro SD do you suggest between Sandisk ultra A1, extreme A1 and Samsung evo (not A1)? There is any way to find a TBW for micro SD like for SSD?

    You find some TBW values for surveillance SD cards but these numbers usually are with movie recording in mind which comes with a write amplification magnitudes lower compared to using an SD card as OS drive in OMV. But as already said: as long as you're using the flashmemory plugin and avoid monitoring (the RRD databases are updated every now and then) you should be fine even with crappy flash media.


    In case you want to really buy SD cards I would prefer SanDisk Ultra Extreme A1 but mostly since I never tried them (want to benchmark those myself) and SanDisk Extreme is known for good reliability. But it shouldn't really matter for an OMV drive since with flashmemory plugin there aren't that much write attempts anyway and write amplification is very low.

  • I prefer SD card over USB thumbdrive if I can for the simple reason that I consider being able to TRIM at least from time to time important.
    But I took the time for these lengthy replies in order to warn for some common misbeliefs since SSDs aren't always superiour especially not when it's about to buy used ones or put them into USB enclosures (my experiments here were rather discouraging, only with a pretty recent JMS578 chip with latest firmware I got TRIM to work. According to others ASM1351 should also allow for TRIM but all reports are based on Startech devices like this so maybe there's a custom firmware needed only Startech provides).


    You find some TBW values for surveillance SD cards but these numbers usually are with movie recording in mind which comes with a write amplification magnitudes lower compared to using an SD card as OS drive in OMV. But as already said: as long as you're using the flashmemory plugin and avoid monitoring (the RRD databases are updated every now and then) you should be fine even with crappy flash media.
    In case you want to really buy SD cards I would prefer SanDisk Ultra Extreme A1 but mostly since I never tried them (want to benchmark those myself) and SanDisk Extreme is known for good reliability. But it shouldn't really matter for an OMV drive since with flashmemory plugin there aren't that much write attempts anyway and write amplification is very low.

    I totally think that those post should be copied into a dedicated topic "Which drive should you choose for you NAS" and stick it on top. I don't think that many people know about trim on SD card, or that you usually can't use it on an SSD inside a case box.

    Intel G4400 - Asrock H170M Pro4S - 8GB ram - Be Quiet Pure Power 11 400 CM - Nanoxia Deep Silence 4 - 6TB Seagate Ironwolf - RAIDZ1 3x10TB WD - OMV 5 - Proxmox Kernel

  • I totally think that those post should be copied into a dedicated topic "Which drive should you choose for you NAS" and stick it on top. I don't think that many people know about trim on SD card, or that you usually can't use it on an SSD inside a case box.


    You should check and see if TRIM works on an SSD inside a USB case. I have at least one that does, it's a Seagate ST480HM0 00-1G5162.


    But all my cheap used Samsung 16GB SSDs do not, and the USB case has nothing to do with it - these drives don't support TRIM at all. But I still run my OMV on them. Am I worried? Nope. I have almost two years running OMV on one of them, 24/7. My pfsense firewall has almost four years running 24/7 on another one and I never even bothered setting it up to use RAMdisks for the logs and RRD data.

    --
    Google is your friend and Bob's your uncle!


    OMV AMD64 7.x on headless Chenbro NR12000 1U 1x 8m Quad Core E3-1220 3.1GHz 32GB ECC RAM.

  • You should check and see if TRIM works on an SSD inside a USB case. I have at least one that does, it's a Seagate ST480HM0 00-1G5162

    Which USB-to-SATA bridge is used here (lsusb output) since this is the more important part with decent SSDs. And which methodology did you use to check if TRIM is really working?

  • You should check and see if TRIM works on an SSD inside a USB case. I have at least one that does, it's a Seagate ST480HM0 00-1G5162.


    But all my cheap used Samsung 16GB SSDs do not, and the USB case has nothing to do with it - these drives don't support TRIM at all. But I still run my OMV on them. Am I worried? Nope. I have almost two years running OMV on one of them, 24/7. My pfsense firewall has almost four years running 24/7 on another one and I never even bothered setting it up to use RAMdisks for the logs and RRD data.

    The thing is: why should I spend 40€ without knowing if I'll have TRIM, if I can spend 25 for a 16GB SD card and a good usb3 adapter?
    If I was certain to have TRIM them 15€ can be worth, otherwise is just complicate things

    Intel G4400 - Asrock H170M Pro4S - 8GB ram - Be Quiet Pure Power 11 400 CM - Nanoxia Deep Silence 4 - 6TB Seagate Ironwolf - RAIDZ1 3x10TB WD - OMV 5 - Proxmox Kernel

  • The thing is: why should I spend 40€ without knowing if I'll have TRIM, if I can spend 25 for a 16GB SD card and a good usb3 adapter?If I was certain to have TRIM them 15€ can be worth, otherwise is just complicate things

    Maybe you missed my point. I have several systems running for years, 24/7 on non-TRIM enabled SSDs. In plain English, I say that for me it does not matter either way. Even simpler, I do not care, those disks didn't cost me even a penny per day of use and so far none of them have failed.

    --
    Google is your friend and Bob's your uncle!


    OMV AMD64 7.x on headless Chenbro NR12000 1U 1x 8m Quad Core E3-1220 3.1GHz 32GB ECC RAM.

    2 Mal editiert, zuletzt von gderf ()

  • I have several systems running for years, 24/7 on non-TRIM enabled SSDs. In plain English, I say that for me it does not matter either way. Even simpler, I do not care, those disks didn't cost me even a penny per day of use and so far none of them have failed.

    Ok, this thread (or this forum in general) is about general recommendations. Not just luck and personal experiences. And your answer/recommendation falls into this category:

    An optimist falls off a 10-story building. As he passes the sixth story, someone yells from the window, “How’s it going?” The man yells back, “So far, so good!”

    Buying used SSDs is not a good idea in general, buying any flash products off of eBay or Aliexpress (or anywhere else where the buyer is not in a position to return goods 'without any questions asked') is not a good idea either, avoiding/preventing TRIM when it's available is a horribly bad idea (but at least when using OMV's flashmemory plugin on all types of flash storage products it doesn't matter that much any more since the flashmemory plugin greatly reduces write amplification).


    For the reasons why simply see above, everything it's explained in detail. And while it's nice for you that the used SSDs you bought somewhere still run flawlessly this shouldn't be a general recommendation (for the reasons above -- for other OMV users this should be a matter of technical understanding and not just ignorance)


    Again wrt TRIM in an USB enclosure: you talked about the SSD used but don't tell us the important part: which USB-to-SATA bridge you used. And also how you determined that TRIM is really working (it's perfectly easy in Linux to add 'discard' to fstab or run fstrim from time and both simply do nothing at all).


    Here's the procedure to verify that TRIM is working (requires a recent hdparm version supporting the '–fibmap' switch which AFAIK is not shipped with any Debian OMV is based on): https://linuxnorth.wordpress.c…im-your-ssd-down-to-size/


    And here are the hassles described needed to get TRIM running with SSD in TRIM capable USB disk enclosures when the kernel misses the necessary support (which is very likely for the vast majority of OMV users not alreay at OMV4/Stretch with latest backports kernel!): http://salutepc.altervista.org…upport-windows-linux.html


    In other words: On a random OMV installation with a random USB enclosure it's almost impossible that a SSD in an USB enclosure will be trimmed ever. And if a flash memory product supports TRIM it should be used if possible. This is not a matter of ignorance but understanding :)

  • If it works (I'm using something similar, but a bit different) I think that the best solution is a dirt cheap (€15 ?!?) M.2 to PCIe adapter and a M.2 SSD.
    PCIe 1x slots are often "wasted" anyway... or just use a spare SATA port.
    If you lack SATA ports maybe it's time to move to ebay: LSI SAS 2008 and an expander will give you enough SATA ports for 2 or 3 cases.

  • It would be nice if any users tell about write mount and time in useof their ssd without trim(usb or sata - no matter).
    I`m just curious.


    My would be 520gb writen after 2 to 3 years(3 time fresh install).


    Smart:
    SanDisk SDSSDA120G
    9 Power_On_Hours_and_Msec -O--CK 000 100 000 - 10864h+00m+00.000s
    230 Life_Curve_Status -O--CK 100 100 000 - 408022220895 (how should i read this? ) .
    241 Lifetime_Writes_GiB ----CK 253 253 000 - 520

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