ZFS, SSD and encryption

[Nikos Kastanas]

>On 7/22/2016 07:48, Nikos Kastanas wrote:

>> I have a Lenovo X220 laptop running FreeBSD 10.3-RELEASE with ZFS and

> >encryption on a plain HDD. I am considering buying a Samsung Pro 850 SSD
to

> >boost performance but I am not sure if TRIM and ZFS+Encryption work well

>> together. After some research online, I found *this page*

> ><https://www.freebsd.org/doc/faq/all-about-zfs.html>which states the

> >following:

>>

> >*Note: *

> >ZFS TRIM may not work with all configurations, such as a ZFS filesystem
on

> >a GELI-backed device.

>>

> >From what I can understand from the above note, I should not use the

> >encryption option when installing FreeBSD with ZFS on an SSD. TRIM will
not

> >work correctly and therefore the SSD performace will be impacted.

>Meh.  Simply not true.  The reason for the "supported feature" flag here

>is that this machine was recently rolled forward to 11.0-BETA1, but I

>have not upgraded the pools yet from the feature set of 10.2.

>

>[karl at NewFS ~]$ zpool status zsr

> pool: zsr

>state: ONLINE

>status: Some supported features are not enabled on the pool. The pool can

>        still be used, but some features are unavailable.

>action: Enable all features using 'zpool upgrade'. Once this is done,

>        the pool may no longer be accessible by software that does not

>support

>        the features. See zpool-features(7) for details.

>  scan: scrub repaired 0 in 0h6m with 0 errors on Sun Jul 17 03:12:01 2016

>config:

>

>        NAME           STATE     READ WRITE CKSUM

>        zsr            ONLINE       0     0     0

>          mirror-0     ONLINE       0     0     0

>            da8p4.eli  ONLINE       0     0     0

>            da9p4.eli  ONLINE       0     0     0

>

>errors: No known data errors

>

>[karl at NewFS ~]$ gpart show da8

>=>       34  468862061  da8  GPT  (224G)

>         34       2014       - free -  (1.0M)

>       2048       1024    1  freebsd-boot  (512K)

>       3072       1024       - free -  (512K)

>       4096   20971520    2  freebsd-zfs  [bootme]  (10G)

>   20975616  134217728    3  freebsd-swap  (64G)

>  155193344  313667584    4  freebsd-zfs  (150G)

>  468860928       1167       - free -  (584K)

>

>da8: <ATA INTEL SSDSC2BP24 0420> Fixed Direct Access SPC-4 SCSI device

>da8: Serial Number BTJR41210025240AGN

>da8: 600.000MB/s transfers

>da8: Command Queueing enabled

>da8: 228936MB (468862128 512 byte sectors)

>

>

>

>root at NewFS:/var/log # sysctl -a|grep trim

>vfs.zfs.trim.max_interval: 1

>vfs.zfs.trim.timeout: 30

>vfs.zfs.trim.txg_delay: 32

>vfs.zfs.trim.enabled: 1

>vfs.zfs.vdev.trim_max_pending: 10000

>vfs.zfs.vdev.trim_max_active: 64

>vfs.zfs.vdev.trim_min_active: 1

>vfs.zfs.vdev.trim_on_init: 1

>kstat.zfs.misc.zio_trim.failed: 0

>kstat.zfs.misc.zio_trim.unsupported: 25748

>kstat.zfs.misc.zio_trim.success: 6120223

>kstat.zfs.misc.zio_trim.bytes: 295371051008

>

>

>And as you can see, TRIM is definitely working (on the devices that can

>handle it); there are also spinning rust disks in this machine, thus the

>"unsupported" reports as well.

>

>HOWEVER, I do suggest (strongly!) that you NOT use the particular SSD

>you are intending to buy as it has no power-loss protection.  Instead,

>buy an Intel 730-series drive (that's what's in this machine); it has

>that protection and it is *EXTREMELY IMPORTANT* as otherwise any power

>event has the potential of silent corruption which is catastrophic --

>especially on an encrypted volume!

>

>That same machine has two other 730s running a Postgresql database (also

>Geli-encrypted) and they're just fine in terms of their wear leveling

>and such; the media "wearout" indicator shows that 95% of the device's

>life remains and they currently have 10,000 power-on-hours.

>

>They'll wear out in something like another 20 years at present use

>rates.... :)

>

>The 480MB version of that drive is currently available for roughly

>$250.  It is not the fastest SSD out there but the differences between

>it and others are small and I have *verified* that the power-loss data

>protection works on these units.  IMHO they're the only "consumer" style

>priced devices that I find acceptable for this reason; the S3500/S3700s

>are good too, but a hell of a lot more money and unless you need the

>write endurance IMHO not worth it.

>

>The 730 series hits the sweet spot in that it has power-loss protection

>that *works* and yet they're reasonably priced.  I own a bunch of them;

>they're in my production servers under FreeBSD and also on my Win10

>desktop machine.

>

>--

>Karl Denninger

>karl at denninger.net <mailto:karl at denninger.net <karl at denninger.net>>

>/The Market Ticker/

>/[S/MIME encrypted email preferred]/


Thank you for your answer. So I guess the warning in the FAQ is probably

outdated.

I will seriously consider your suggestion considering the Intel SSD.

Thank you for your help