Advice on mirrored USB vs single SSD for boot

[Ericloewe]

I wonder if it would work to add a third mirror device and then remove the defective one?

Should be possible.

 

[joeschmuck]

I wonder if it would work to add a third mirror device and then remove the defective one?

I don't see what advantage that would bring but if you try it, you should add any results to the bug report. It's terrible that this bug has been ignored for so long. I'm sure it's a manpower/money issue, I deal with that everyday and I hate cutting something basic out of a product just because I'm not specifically funded for it but that is the way of the world so we can charge our customers more to add those features later. I'm sure iXsystems has to manage the manpower/money thing as well, especially for a free product.

 

[rogerh]

I don't see what advantage that would bring but if you try it, you should add any results to the bug report. It's terrible that this bug has been ignored for so long. I'm sure it's a manpower/money issue, I deal with that everyday and I hate cutting something basic out of a product just because I'm not specifically funded for it but that is the way of the world so we can charge our customers more to add those features later. I'm sure iXsystems has to manage the manpower/money thing as well, especially for a free product.

The advantage would be that the bug has apparently been resolved for the 'adding a mirror drive' case. So the third drive would presumably get grub installed. But I can't test it because I am booting from two SSDs and I haven't got a spare SATA port for a third one.

Of course, everything does come down to money and resources in the end; but I get the impression they can't think of a way to solve it without massive rewriting which would take so long to test that it would be obsolete before it was ready.

 

[Linkman]

Thanks for all the input! This generated more discussion than I expected, and I appreciate the advice.

All things being equal, I think would stick with my mirrored USB flash drives until there was some sort of failure, and then replace them with an SSD, as the discussion pointed me toward the SSD, but not heavily enough to change what's working now. However, not all things are equal, so what I am in process of doing is replacing the 120 GB SSD (backed by a 500 GB WD Black) in my main desktop box with a new 500 GB Crucial SSD (keeping the Black drive as a first level backup device), pushing the 120 GB SSD down to my smaller desktop box, and moving that box's current 60 GB SSD into the FreeNAS box as its boot device to replace the USB flash drives.

I'll also be adding a pair of mirrored 2 TB WD Green drives as a separate pool to the FreeNAS box (that'll be my jails' playground), adding a second 16 GB of ECC RAM, and doing the LSI firmware flash and 9.3.1 upgrade as well, since there isn't really anything of import on the FreeNAS machine yet.

 

[joeschmuck]

Well it's a good thing you have it figured out and I do the same thing, re-purpose parts that can be used elsewhere. The 60GB SSD will be more than fine. Ensure you check the life remaining (wear level) on that drive if it's been in use for a long time. No need to install a SSD that is nearing the end of it's useful life.

 

[ianmcginley]

I didn't want to start a new thread for it, and I had read quite a bit, but how do you set the ashift correctly for your boot ssd when it does a ZFS root?

 

[Ericloewe]

I didn't want to start a new thread for it, and I had read quite a bit, but how do you set the ashift correctly for your boot ssd when it does a ZFS root?

Don't worry about it. Just use it as it's supposed to be used.

 

[joeschmuck]

Don't worry about it. Just use it as it's supposed to be used.

Agreed. You do not need to worry about the ashift for a boot device as a SSD will take well over the lifespan of the NAS before it remotely comes close to wearing out. I guess you could but you should find out if in fact the ashift is off in the first place. I don't know if it is for FreeNAS 9.3.1.

 

[ianmcginley]

Agreed. You do not need to worry about the ashift for a boot device as a SSD will take well over the lifespan of the NAS before it remotely comes close to wearing out. I guess you could but you should find out if in fact the ashift is off in the first place. I don't know if it is for FreeNAS 9.3.1.

Thanks to both for the responses!

 

[NicklowiczComputers LLC]

So I know this is an old thread but I must chimed in mine as has been up for about 2 years now and I started originally with a standard hard drive. than after reading a lot of the forms changed to redundant to USB drives during that time I have already replaced them in sets 7 times as my nas keeps emailing me telling me that one or more of the USB drive fails and then it gives a checksum number. Well today it happened again which brings me to this form .2x120 GB ssd which I know is overkill .I do not have any open SATA ports on my current rig as I have six drives connected but I was wondering what if I was to use one of those small laptop to USB adapters plug the laptop SSD into that and then plug that into the USB port would that give me the benefits of SSD over USB or would this just be a waste of Technology I like the idea of having the mirrored USBS only because,yes you have to go into the BIOS and change it but if it goes down it is a simple fix and then you can pop a new Drive-In have it resilver and your up running and backup is in place. I view this technique more as a redundant backup in the event your dry fails you can switch to the backup and then rebuild once it's back up. ( thus when it has went down I did not have to do any type of reinstall or configuration I just tell the BIOS to boot from the second USB get it back up put new one back in and tell it to replace)

So question would a USB to SSD laptop converter over USB work and would it be as fast as using a SATA connector?
Eventually I will get a drive bay that will be external to the HP server I have and that will take over being that it has ECC memory Etc but for now I am running this desktop.

I do I.t Corp for a living and swear by freenas hasn't let me down yet

 

[Ericloewe]

would a USB to SSD laptop converter over USB work

Yes.

would it be as fast as using a SATA connector?

No, but it's the boot pool. Who cares.

 

[NicklowiczComputers LLC]

Yes.


No, but it's the boot pool. Who cares.

Thanks for the quick response. For now I used one I have (the kind the requires external power) and plugged in where one of the failed usb drivers was removed, hit replace and it detected it. So I am giving this a test. I think I may find some smaller ssd (as 128gb x2 is indeed a waste) but we will see how this works and if so I may get one of the adapters that are small (just usb to ssd) and post the findings of them as well as screenshot incase someone wants to have the dual usb idea with the reliability of SSD and without waisting the port or dealing with the issues I have (constantly replacing failed cheap USB thums)

The pain with this is although cheap it adds up constantly running out and getting new set

 

[zoomzoom]

@NicklowiczComputers LLC Unless you have an older 32/64GB cache SSD, it's a waste for a few reasons:

• It takes up a SATA port, and if its not SATA3, a USB3 flash drive will operate close to SATA2 speeds (PNY's do 190/130 r/w)
• While booting may be sped up a bit with a SSD, beyond that, there's very little benefit.
• It will take a significant amount of time (several years, or quite a few boot environments/boot snapshots, to fill a 32GB USB drive).

 

[NicklowiczComputers LLC]

@NicklowiczComputers LLC Unless you have an older 32/64GB cache SSD, it's a waste for a few reasons:

• It takes up a SATA port, and if its not SATA3, a USB3 flash drive will operate close to SATA2 speeds (PNY's do 190/130 r/w)
• While booting may be sped up a bit with a SSD, beyond that, there's very little benefit.
• It will take a significant amount of time (several years, or quite a few boot environments/boot snapshots) to fill a 32GB USB drive).

I was referring to putting it on the usb but via an adapter so the sata wouldn't be connected to a sata port on pc,but connected with an adapter over usb thus be seen as usb thumb but being reliable as ssd

Thanks for the response

 

[rogerh]

I think using 128GB SSDs is only a waste if you can get decent quality smaller one's cheaper, and if you have a better use for the 128GB ones you already have.

 

[NicklowiczComputers LLC]

I think using 128GB SSDs is only a waste if you can get decent quality smaller one's cheaper, and if you have a better use for the 128GB ones you already have.

Yes. I am currently using 1 did resilver with other being usb. I will do both and it should be ok running these over usb?

 

[cneeper]

So, what about not using FreeNAS (ZFS) to mirror the boot pool. If your motherboard supports software (firmware) RAID1 (the one I'm spec'ing out does), what about mirroring the boot devices outside of the operating system. That provides the benefit of always booting regardless of which storage device failed. It also allows you to replace the storage device and "resilver" it on the fly with no downtime at all. Naturally, you want JBOD for all of the other storage devices used in FreeNAS, but is there any problem with doing a hardware or software RAID1 for only the boot devices?

(New to FreeNAS, definitely not new to NASes in general or IT. And admittedly, I haven't done my homework on this topic, so it may have been covered elsewhere and I haven't found it yet.)

 

[wblock]

Motherboard "RAID" is... well, I actively avoid it, with or without ZFS. It also has the problem of hiding the hardware from ZFS, which defeats some of the most important things that ZFS does. I use a single SSD, 120 or 128G is fine. 64G drives are not appreciably cheaper, unless you buy special small ones or used ones. Don't do that. 120G is tiny by current standards, and cheap, the price of two or three quality USB drives and much more reliable. The space is not being wasted, it's being used by the drive for wear leveling. And there is room for the new boot environments that are created each time you upgrade.

 

[Stux]

Motherboard RAID’s only actual capability is preventing non motherboard raid aware OSes from stomping on the motherboard raid disks. The rest of the RAIDing is performed by the OS.

With modern motherboards, which have an m2 slot, a cheapish option can actually be an Intel Optane 16/32GB NVMe drive! And you don’t lose a Sata port.

 

[Ericloewe]

If your motherboard supports software (firmware) RAID1 (the one I'm spec'ing out does), what about mirroring the boot devices outside of the operating system.

You only think it does. It only works with a Windows driver.

That provides the benefit of always booting regardless of which storage device failed.

All parts of a mirror have GRUB installed on them to allow any of them to boot in most failure scenarios, so that's not as big of an advantage as it might sound.