On Mar 6, 2018, at 12:39 PM, Walter Parker <walt...@gmail.com> wrote:
> On Mon, Mar 5, 2018 at 6:38 PM, Curtis Maurand <cmaur...@xyonet.com> wrote: > >> ZFS is a memory hog. you need 1 GB of RAM for each TB of disk. > > > Curtis, can you provide some more details? I have been testing this for the > last couple of weeks and ZFS doesn't require 1G for each TB to function > (which is the standard meaning of need). > From my direct testing and experience 1G per TB is a rule of thumb for > suggested memory sizing on general purpose servers. Do you have specific > information that violating this rule of thumb will cause functional issues? > > To be more blunt, was this a case of drive by nerd sniping or do you know > something that will cause my specific use case to fail at some point in the > future? The "1G for each TB" sounds like the rule of thumb for when you plan to enable deduplication on a dataset. ZFS deduplication can be a disastrous memory hog (or else completely ruin your performance if you don't have sufficient ARC memory/resources), which is why many people do not enable it unless they've made a serious conscious decision to do so. I ran ZFS on a 1--2 GB RAM FreeBSD/i386 system for years and it was stable. I have to tune KVM and restrict ARC RAM consumption, but once I did that I had no problems. It's my experience that ZFS is more stable and tested on FreeBSD/amd64. Cheers, Paul. > > > Walter > > > >> On 3/1/2018 1:49 AM, Walter Parker wrote: >> >>> Forgot to CC the list. >>> >>> On Wed, Feb 28, 2018 at 10:13 PM, Walter Parker <walt...@gmail.com> >>> wrote: >>> >>> Thank you for the backup script. >>>> >>>> By my calculations, 2G should be enough. If I limit the ARC cache to 1G, >>>> that leaves 1G for applications & kernel memory. As I'm not serving the >>>> 6TB >>>> drive up as a file server, but using it for one specific task (to receive >>>> the backups from one host) I figure that I don't need lots of memory. ZFS >>>> as a quick file server or busy server needs lots of memory to be quick. >>>> I've seen testing showing ZFS doing fast file copies on as little as 768M >>>> total system after proper memory tuning. >>>> >>>> I need ZFS because it is the only file system that can receive >>>> incremental >>>> ZFS snapshots and apply them. I have not setup the ZFS backup software >>>> yes, >>>> so I'm just using rsnapshot. First time it ran, it filled all 1G of the >>>> cache. I rebooted the firewall afterwards and now ZFS with 60-100M of >>>> usage >>>> (the amount of data that rsync updates on a daily basis is pretty small). >>>> Right now, the data from the other server is ~8.8G, compressed to 1.7G >>>> with >>>> lz4. >>>> >>>> When I get the full backup running, I will be ~1.5TB in size. ZFS >>>> snapshots should be pretty small and quick (as it can send just the data >>>> that was updated without having to walk the entire filesystem). An rsync >>>> backup would have to walk the whole system to find all of the changes. >>>> Most >>>> of the data on the system doesn't change (as it is a media library). >>>> >>>> I'll post back more results if people are interested, after I get the >>>> backup software working (I'm thinking about using ZapZend). >>>> >>>> >>>> Walter >>>> >>>> >>>> >>>> On Wed, Feb 28, 2018 at 8:54 PM, ED Fochler <soek...@liquidbinary.com> >>>> wrote: >>>> >>>> I feel like I'm late in responding to this, but I have to say that 2GB of >>>>> RAM doesn't seem like nearly enough for a 6TB zfs volume. ZFS is great >>>>> in >>>>> a lot of ways, but is a RAM consuming monster. For something RAM >>>>> limited >>>>> like the 2220 I'd use a different, simpler file format. Then I'd use >>>>> rsync >>>>> based snapshots. >>>>> >>>>> Here's my personal backup script. :-) I haven't tried it FROM pfsense, >>>>> but I've used it to back up pfsense. >>>>> >>>>> ED. >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> On 2018, Feb 21, at 12:23 PM, Walter Parker <walt...@gmail.com> wrote: >>>>>> >>>>>> Hi, >>>>>> >>>>>> I have 2.4.2 installed on an SG-2220 from Netgate [nice box]. I just >>>>>> >>>>> bought >>>>> >>>>>> a 6TB powered USB drive from Costco and it works great (the drive has >>>>>> >>>>> its >>>>> >>>>>> own power supply and a USB hub). I want to use it take ZFS backups from >>>>>> >>>>> my >>>>> >>>>>> home server. >>>>>> >>>>>> I edited /boot/loader.conf.local and /etc/rc.conf.local to load ZFS on >>>>>> >>>>> boot >>>>> >>>>>> and created a pool and a file system. That worked, but the memory ran >>>>>> >>>>> low >>>>> >>>>>> so I restricted the ARC cache to 1G to keep a bit more memory free and >>>>>> rebooted. When the system rebooted it did not remount the pool (and >>>>>> therefore the file system) because the pool what marked as in use by >>>>>> another system (itself). That means that the pool was not properly >>>>>> exported/umounted at shutdown. >>>>>> >>>>>> Taking a quick look a rc.shutdown, I notice that it calls a customized >>>>>> pfsense shutdown script at the beginning and then exits. Is there a >>>>>> good >>>>>> place in the configuration where I can put/call the proper zfs shutdown >>>>>> script so that the pool is properly stopped/exported so that it imports >>>>>> correctly on boot? >>>>>> >>>>>> >>>>>> Walter >>>>>> >>>>>> -- >>>>>> The greatest dangers to liberty lurk in insidious encroachment by men >>>>>> of >>>>>> zeal, well-meaning but without understanding. -- Justice Louis D. >>>>>> >>>>> Brandeis >>>>> >>>>>> _______________________________________________ >>>>>> pfSense mailing list >>>>>> https://lists.pfsense.org/mailman/listinfo/list >>>>>> Support the project with Gold! https://pfsense.org/gold >>>>>> >>>>> >>>>> >>>>> >>>> -- >>>> The greatest dangers to liberty lurk in insidious encroachment by men of >>>> zeal, well-meaning but without understanding. -- Justice Louis D. >>>> Brandeis >>>> >>>> >>> >>> >> -- >> Best Regards >> Curtis Maurand >> Principal >> Xyonet Web Hosting >> mailto:cmaur...@xyonet.com >> http://www.xyonet.com >> >> _______________________________________________ >> pfSense mailing list >> https://lists.pfsense.org/mailman/listinfo/list >> Support the project with Gold! https://pfsense.org/gold >> > > > > -- > The greatest dangers to liberty lurk in insidious encroachment by men of > zeal, well-meaning but without understanding. -- Justice Louis D. Brandeis > _______________________________________________ > pfSense mailing list > https://lists.pfsense.org/mailman/listinfo/list > Support the project with Gold! https://pfsense.org/gold > _______________________________________________ pfSense mailing list https://lists.pfsense.org/mailman/listinfo/list Support the project with Gold! https://pfsense.org/gold
