Date: Tue, 18 Jan 2022 09:51:37 -0500 From: Rich <rincebrain@gmail.com> To: Alan Somers <asomers@freebsd.org> Cc: Florent Rivoire <florent@rivoire.fr>, freebsd-fs <freebsd-fs@freebsd.org> Subject: Re: [zfs] recordsize: unexpected increase of disk usage when increasing it Message-ID: <CAOeNLuppbdRbC-bsDEqKKUBMO8KKvaLpVs-OcSA2AF2tO5b03w@mail.gmail.com> In-Reply-To: <CAOtMX2g4KduvFA6W062m93jnrJcjQ9KSzkXjb42F1nvhPWaZsw@mail.gmail.com> References: <CADzRhsEsZMGE-SoeWLMG9NTtkwhhy6OGQQ046m9AxGFbp5h_kQ@mail.gmail.com> <CAOeNLuopaY3j7P030KO4LMwU3BOU5tXiu6gRsSKsDrFEuGKuaA@mail.gmail.com> <CAOtMX2h=miZt=6__oAhPVzsK9ReShy6nG%2BaTiudvK_jp2sQKJQ@mail.gmail.com> <CAOeNLuoQLgKn673FVotxdoDC3HBr1_j%2BzY0t9-uVj7N%2BFkoe1Q@mail.gmail.com> <CAOtMX2g4KduvFA6W062m93jnrJcjQ9KSzkXjb42F1nvhPWaZsw@mail.gmail.com>
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--00000000000082918105d5dc68dc Content-Type: text/plain; charset="UTF-8" 2.1M /workspace/test1M/1 - Rich On Tue, Jan 18, 2022 at 9:47 AM Alan Somers <asomers@freebsd.org> wrote: > Yeah, it does. Just check "du -sh <FILENAME>". zdb there is showing > you the logical size of the record, but it isn't showing how many disk > blocks are actually allocated. > > On Tue, Jan 18, 2022 at 7:30 AM Rich <rincebrain@gmail.com> wrote: > > > > Really? I didn't know it would still trim the tails on files with > compression off. > > > > ... > > > > size 1179648 > > parent 34 > > links 1 > > pflags 40800000004 > > Indirect blocks: > > 0 L1 DVA[0]=<3:c02b96c000:1000> > DVA[1]=<3:c810733000:1000> [L1 ZFS plain file] skein lz4 unencrypted LE > contiguous unique double size=20000L/1000P birth=35675472L/35675472P fill=2 > cksum=5cfba24b351a09aa:8bd9dfef87c5b625:906ed5c3252943db:bed77ce51ad540d4 > > 0 L0 DVA[0]=<2:a0827db4000:100000> [L0 ZFS plain file] > skein uncompressed unencrypted LE contiguous unique single > size=100000L/100000P birth=35675472L/35675472P fill=1 > cksum=95b06edf60e5f54c:af6f6950775d0863:8fc28b0783fcd9d3:2e44676e48a59360 > > 100000 L0 DVA[0]=<2:a0827eb4000:100000> [L0 ZFS plain file] > skein uncompressed unencrypted LE contiguous unique single > size=100000L/100000P birth=35675472L/35675472P fill=1 > cksum=62a1f05769528648:8197c8a05ca9f1fb:a750c690124dd2e0:390bddc4314cd4c3 > > > > It seems not? > > > > - Rich > > > > > > On Tue, Jan 18, 2022 at 9:23 AM Alan Somers <asomers@freebsd.org> wrote: > >> > >> On Tue, Jan 18, 2022 at 7:13 AM Rich <rincebrain@gmail.com> wrote: > >> > > >> > Compression would have made your life better here, and possibly also > made it clearer what's going on. > >> > > >> > All records in a file are going to be the same size pre-compression - > so if you set the recordsize to 1M and save a 131.1M file, it's going to > take up 132M on disk before compression/raidz overhead/whatnot. > >> > >> Not true. ZFS will trim the file's tails even without compression > enabled. > >> > >> > > >> > Usually compression saves you from the tail padding actually > requiring allocation on disk, which is one reason I encourage everyone to > at least use lz4 (or, if you absolutely cannot for some reason, I guess zle > should also work for this one case...) > >> > > >> > But I would say it's probably the sum of last record padding across > the whole dataset, if you don't have compression on. > >> > > >> > - Rich > >> > > >> > On Tue, Jan 18, 2022 at 8:57 AM Florent Rivoire <florent@rivoire.fr> > wrote: > >> >> > >> >> TLDR: I rsync-ed the same data twice: once with 128K recordsize and > >> >> once with 1M, and the allocated size on disk is ~3% bigger with 1M. > >> >> Why not smaller ? > >> >> > >> >> > >> >> Hello, > >> >> > >> >> I would like some help to understand how the disk usage evolves when > I > >> >> change the recordsize. > >> >> > >> >> I've read several articles/presentations/forums about recordsize in > >> >> ZFS, and if I try to summarize, I mainly understood that: > >> >> - recordsize is the "maximum" size of "objects" (so "logical blocks") > >> >> that zfs will create for both -data & metadata, then each object is > >> >> compressed and allocated to one vdev, splitted into smaller (ashift > >> >> size) "physical" blocks and written on disks > >> >> - increasing recordsize is usually good when storing large files that > >> >> are not modified, because it limits the nb of metadata objects > >> >> (block-pointers), which has a positive effect on performance > >> >> - decreasing recordsize is useful for "databases-like" workloads (ie: > >> >> small random writes inside existing objects), because it avoids write > >> >> amplification (read-modify-write a large object for a small update) > >> >> > >> >> Today, I'm trying to observe the effect of increasing recordsize for > >> >> *my* data (because I'm also considering defining special_small_blocks > >> >> & using SSDs as "special", but not tested nor discussed here, just > >> >> recordsize). > >> >> So, I'm doing some benchmarks on my "documents" dataset (details in > >> >> "notes" below), but the results are really strange to me. > >> >> > >> >> When I rsync the same data to a freshly-recreated zpool: > >> >> A) with recordsize=128K : 226G allocated on disk > >> >> B) with recordsize=1M : 232G allocated on disk => bigger than 128K > ?!? > >> >> > >> >> I would clearly expect the other way around, because bigger > recordsize > >> >> generates less metadata so smaller disk usage, and there shouldn't be > >> >> any overhead because 1M is just a maximum and not a forced size to > >> >> allocate for every object. > >> > >> A common misconception. The 1M recordsize applies to every newly > >> created object, and every object must use the same size for all of its > >> records (except possibly the last one). But objects created before > >> you changed the recsize will retain their old recsize, file tails have > >> a flexible recsize. > >> > >> >> I don't mind the increased usage (I can live with a few GB more), but > >> >> I would like to understand why it happens. > >> > >> You might be seeing the effects of sparsity. ZFS is smart enough not > >> to store file holes (and if any kind of compression is enabled, it > >> will find long runs of zeroes and turn them into holes). If your data > >> contains any holes that are >= 128 kB but < 1MB, then they can be > >> stored as holes with a 128 kB recsize but must be stored as long runs > >> of zeros with a 1MB recsize. > >> > >> However, I would suggest that you don't bother. With a 128kB recsize, > >> ZFS has something like a 1000:1 ratio of data:metadata. In other > >> words, increasing your recsize can save you at most 0.1% of disk > >> space. Basically, it doesn't matter. What it _does_ matter for is > >> the tradeoff between write amplification and RAM usage. 1000:1 is > >> comparable to the disk:ram of many computers. And performance is more > >> sensitive to metadata access times than data access times. So > >> increasing your recsize can help you keep a greater fraction of your > >> metadata in ARC. OTOH, as you remarked increasing your recsize will > >> also increase write amplification. > >> > >> So to summarize: > >> * Adjust compression settings to save disk space. > >> * Adjust recsize to save RAM. > >> > >> -Alan > >> > >> >> > >> >> I tried to give all the details of my tests below. > >> >> Did I do something wrong ? Can you explain the increase ? > >> >> > >> >> Thanks ! > >> >> > >> >> > >> >> > >> >> =============================================== > >> >> A) 128K > >> >> ========== > >> >> > >> >> # zpool destroy bench > >> >> # zpool create -o ashift=12 bench > >> >> /dev/gptid/3c0f5cbc-b0ce-11ea-ab91-c8cbb8cc3ad4 > >> >> > >> >> # rsync -av --exclude '.zfs' /mnt/tank/docs-florent/ /bench > >> >> [...] > >> >> sent 241,042,476,154 bytes received 353,838 bytes 81,806,492.45 > bytes/sec > >> >> total size is 240,982,439,038 speedup is 1.00 > >> >> > >> >> # zfs get recordsize bench > >> >> NAME PROPERTY VALUE SOURCE > >> >> bench recordsize 128K default > >> >> > >> >> # zpool list -v bench > >> >> NAME SIZE ALLOC FREE > >> >> CKPOINT EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT > >> >> bench 2.72T 226G 2.50T > >> >> - - 0% 8% 1.00x ONLINE - > >> >> gptid/3c0f5cbc-b0ce-11ea-ab91-c8cbb8cc3ad4 2.72T 226G 2.50T > >> >> - - 0% 8.10% - ONLINE > >> >> > >> >> # zfs list bench > >> >> NAME USED AVAIL REFER MOUNTPOINT > >> >> bench 226G 2.41T 226G /bench > >> >> > >> >> # zfs get all bench |egrep "(used|referenced|written)" > >> >> bench used 226G - > >> >> bench referenced 226G - > >> >> bench usedbysnapshots 0B - > >> >> bench usedbydataset 226G - > >> >> bench usedbychildren 1.80M - > >> >> bench usedbyrefreservation 0B - > >> >> bench written 226G - > >> >> bench logicalused 226G - > >> >> bench logicalreferenced 226G - > >> >> > >> >> # zdb -Lbbbs bench > zpool-bench-rcd128K.zdb > >> >> > >> >> > >> >> > >> >> =============================================== > >> >> B) 1M > >> >> ========== > >> >> > >> >> # zpool destroy bench > >> >> # zpool create -o ashift=12 bench > >> >> /dev/gptid/3c0f5cbc-b0ce-11ea-ab91-c8cbb8cc3ad4 > >> >> # zfs set recordsize=1M bench > >> >> > >> >> # rsync -av --exclude '.zfs' /mnt/tank/docs-florent/ /bench > >> >> [...] > >> >> sent 241,042,476,154 bytes received 353,830 bytes 80,173,899.88 > bytes/sec > >> >> total size is 240,982,439,038 speedup is 1.00 > >> >> > >> >> # zfs get recordsize bench > >> >> NAME PROPERTY VALUE SOURCE > >> >> bench recordsize 1M local > >> >> > >> >> # zpool list -v bench > >> >> NAME SIZE ALLOC FREE > >> >> CKPOINT EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT > >> >> bench 2.72T 232G 2.49T > >> >> - - 0% 8% 1.00x ONLINE - > >> >> gptid/3c0f5cbc-b0ce-11ea-ab91-c8cbb8cc3ad4 2.72T 232G 2.49T > >> >> - - 0% 8.32% - ONLINE > >> >> > >> >> # zfs list bench > >> >> NAME USED AVAIL REFER MOUNTPOINT > >> >> bench 232G 2.41T 232G /bench > >> >> > >> >> # zfs get all bench |egrep "(used|referenced|written)" > >> >> bench used 232G - > >> >> bench referenced 232G - > >> >> bench usedbysnapshots 0B - > >> >> bench usedbydataset 232G - > >> >> bench usedbychildren 1.96M - > >> >> bench usedbyrefreservation 0B - > >> >> bench written 232G - > >> >> bench logicalused 232G - > >> >> bench logicalreferenced 232G - > >> >> > >> >> # zdb -Lbbbs bench > zpool-bench-rcd1M.zdb > >> >> > >> >> > >> >> > >> >> =============================================== > >> >> Notes: > >> >> ========== > >> >> > >> >> - the source dataset contains ~50% of pictures (raw files and jpg), > >> >> and also some music, various archived documents, zip, videos > >> >> - no change on the source dataset while testing (cf size logged by > resync) > >> >> - I repeated the tests twice (128K, then 1M, then 128K, then 1M), and > >> >> same results > >> >> - probably not important here, but: > >> >> /dev/gptid/3c0f5cbc-b0ce-11ea-ab91-c8cbb8cc3ad4 is a Red 3TB CMR > >> >> (WD30EFRX), and /mnt/tank/docs-florent/ is a 128K-recordsize dataset > >> >> on another zpool that I never tweaked except ashit=12 (because using > >> >> the same model of Red 3TB) > >> >> > >> >> # zfs --version > >> >> zfs-2.0.6-1 > >> >> zfs-kmod-v2021120100-zfs_a8c7652 > >> >> > >> >> # uname -a > >> >> FreeBSD xxxxxxxxx 12.2-RELEASE-p11 FreeBSD 12.2-RELEASE-p11 > >> >> 75566f060d4(HEAD) TRUENAS amd64 > --00000000000082918105d5dc68dc Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable <div dir=3D"ltr">2.1M =C2=A0 =C2=A0/workspace/test1M/1<br><div><br></div><d= iv>- Rich</div></div><br><div class=3D"gmail_quote"><div dir=3D"ltr" class= =3D"gmail_attr">On Tue, Jan 18, 2022 at 9:47 AM Alan Somers <<a href=3D"= mailto:asomers@freebsd.org">asomers@freebsd.org</a>> wrote:<br></div><bl= ockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-lef= t:1px solid rgb(204,204,204);padding-left:1ex">Yeah, it does.=C2=A0 Just ch= eck "du -sh <FILENAME>".=C2=A0 zdb there is showing<br> you the logical size of the record, but it isn't showing how many disk<= br> blocks are actually allocated.<br> <br> On Tue, Jan 18, 2022 at 7:30 AM Rich <<a href=3D"mailto:rincebrain@gmail= .com" target=3D"_blank">rincebrain@gmail.com</a>> wrote:<br> ><br> > Really? I didn't know it would still trim the tails on files with = compression off.<br> ><br> > ...<br> ><br> >=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0size=C2=A0 =C2=A0 1179648<br> >=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0parent=C2=A0 34<br> >=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0links=C2=A0 =C2=A01<br> >=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0pflags=C2=A0 40800000004<br> > Indirect blocks:<br> >=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 0 L1=C2=A0 DVA[= 0]=3D<3:c02b96c000:1000> DVA[1]=3D<3:c810733000:1000> [L1 ZFS p= lain file] skein lz4 unencrypted LE contiguous unique double size=3D20000L/= 1000P birth=3D35675472L/35675472P fill=3D2 cksum=3D5cfba24b351a09aa:8bd9dfe= f87c5b625:906ed5c3252943db:bed77ce51ad540d4<br> >=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 0=C2=A0 L0 DVA[= 0]=3D<2:a0827db4000:100000> [L0 ZFS plain file] skein uncompressed un= encrypted LE contiguous unique single size=3D100000L/100000P birth=3D356754= 72L/35675472P fill=3D1 cksum=3D95b06edf60e5f54c:af6f6950775d0863:8fc28b0783= fcd9d3:2e44676e48a59360<br> >=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0100000=C2=A0 L0 DVA[0]=3D<2= :a0827eb4000:100000> [L0 ZFS plain file] skein uncompressed unencrypted = LE contiguous unique single size=3D100000L/100000P birth=3D35675472L/356754= 72P fill=3D1 cksum=3D62a1f05769528648:8197c8a05ca9f1fb:a750c690124dd2e0:390= bddc4314cd4c3<br> ><br> > It seems not?<br> ><br> > - Rich<br> ><br> ><br> > On Tue, Jan 18, 2022 at 9:23 AM Alan Somers <<a href=3D"mailto:asom= ers@freebsd.org" target=3D"_blank">asomers@freebsd.org</a>> wrote:<br> >><br> >> On Tue, Jan 18, 2022 at 7:13 AM Rich <<a href=3D"mailto:rincebr= ain@gmail.com" target=3D"_blank">rincebrain@gmail.com</a>> wrote:<br> >> ><br> >> > Compression would have made your life better here, and possib= ly also made it clearer what's going on.<br> >> ><br> >> > All records in a file are going to be the same size pre-compr= ession - so if you set the recordsize to 1M and save a 131.1M file, it'= s going to take up 132M on disk before compression/raidz overhead/whatnot.<= br> >><br> >> Not true.=C2=A0 ZFS will trim the file's tails even without co= mpression enabled.<br> >><br> >> ><br> >> > Usually compression saves you from the tail padding actually = requiring allocation on disk, which is one reason I encourage everyone to a= t least use lz4 (or, if you absolutely cannot for some reason, I guess zle = should also work for this one case...)<br> >> ><br> >> > But I would say it's probably the sum of last record padd= ing across the whole dataset, if you don't have compression on.<br> >> ><br> >> > - Rich<br> >> ><br> >> > On Tue, Jan 18, 2022 at 8:57 AM Florent Rivoire <<a href= =3D"mailto:florent@rivoire.fr" target=3D"_blank">florent@rivoire.fr</a>>= wrote:<br> >> >><br> >> >> TLDR: I rsync-ed the same data twice: once with 128K reco= rdsize and<br> >> >> once with 1M, and the allocated size on disk is ~3% bigge= r with 1M.<br> >> >> Why not smaller ?<br> >> >><br> >> >><br> >> >> Hello,<br> >> >><br> >> >> I would like some help to understand how the disk usage e= volves when I<br> >> >> change the recordsize.<br> >> >><br> >> >> I've read several articles/presentations/forums about= recordsize in<br> >> >> ZFS, and if I try to summarize, I mainly understood that:= <br> >> >> - recordsize is the "maximum" size of "obj= ects" (so "logical blocks")<br> >> >> that zfs will create for both=C2=A0 -data & metadata,= then each object is<br> >> >> compressed and allocated to one vdev, splitted into small= er (ashift<br> >> >> size) "physical" blocks and written on disks<br= > >> >> - increasing recordsize is usually good when storing larg= e files that<br> >> >> are not modified, because it limits the nb of metadata ob= jects<br> >> >> (block-pointers), which has a positive effect on performa= nce<br> >> >> - decreasing recordsize is useful for "databases-lik= e" workloads (ie:<br> >> >> small random writes inside existing objects), because it = avoids write<br> >> >> amplification (read-modify-write a large object for a sma= ll update)<br> >> >><br> >> >> Today, I'm trying to observe the effect of increasing= recordsize for<br> >> >> *my* data (because I'm also considering defining spec= ial_small_blocks<br> >> >> & using SSDs as "special", but not tested n= or discussed here, just<br> >> >> recordsize).<br> >> >> So, I'm doing some benchmarks on my "documents&q= uot; dataset (details in<br> >> >> "notes" below), but the results are really stra= nge to me.<br> >> >><br> >> >> When I rsync the same data to a freshly-recreated zpool:<= br> >> >> A) with recordsize=3D128K : 226G allocated on disk<br> >> >> B) with recordsize=3D1M : 232G allocated on disk =3D> = bigger than 128K ?!?<br> >> >><br> >> >> I would clearly expect the other way around, because bigg= er recordsize<br> >> >> generates less metadata so smaller disk usage, and there = shouldn't be<br> >> >> any overhead because 1M is just a maximum and not a force= d size to<br> >> >> allocate for every object.<br> >><br> >> A common misconception.=C2=A0 The 1M recordsize applies to every n= ewly<br> >> created object, and every object must use the same size for all of= its<br> >> records (except possibly the last one).=C2=A0 But objects created = before<br> >> you changed the recsize will retain their old recsize, file tails = have<br> >> a flexible recsize.<br> >><br> >> >> I don't mind the increased usage (I can live with a f= ew GB more), but<br> >> >> I would like to understand why it happens.<br> >><br> >> You might be seeing the effects of sparsity.=C2=A0 ZFS is smart en= ough not<br> >> to store file holes (and if any kind of compression is enabled, it= <br> >> will find long runs of zeroes and turn them into holes).=C2=A0 If = your data<br> >> contains any holes that are >=3D 128 kB but < 1MB, then they= can be<br> >> stored as holes with a 128 kB recsize but must be stored as long r= uns<br> >> of zeros with a 1MB recsize.<br> >><br> >> However, I would suggest that you don't bother.=C2=A0 With a 1= 28kB recsize,<br> >> ZFS has something like a 1000:1 ratio of data:metadata.=C2=A0 In o= ther<br> >> words, increasing your recsize can save you at most 0.1% of disk<b= r> >> space.=C2=A0 Basically, it doesn't matter.=C2=A0 What it _does= _ matter for is<br> >> the tradeoff between write amplification and RAM usage.=C2=A0 1000= :1 is<br> >> comparable to the disk:ram of many computers.=C2=A0 And performanc= e is more<br> >> sensitive to metadata access times than data access times.=C2=A0 S= o<br> >> increasing your recsize can help you keep a greater fraction of yo= ur<br> >> metadata in ARC.=C2=A0 OTOH, as you remarked increasing your recsi= ze will<br> >> also increase write amplification.<br> >><br> >> So to summarize:<br> >> * Adjust compression settings to save disk space.<br> >> * Adjust recsize to save RAM.<br> >><br> >> -Alan<br> >><br> >> >><br> >> >> I tried to give all the details of my tests below.<br> >> >> Did I do something wrong ? Can you explain the increase ?= <br> >> >><br> >> >> Thanks !<br> >> >><br> >> >><br> >> >><br> >> >> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D<br> >> >> A) 128K<br> >> >> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D<br> >> >><br> >> >> # zpool destroy bench<br> >> >> # zpool create -o ashift=3D12 bench<br> >> >> /dev/gptid/3c0f5cbc-b0ce-11ea-ab91-c8cbb8cc3ad4<br> >> >><br> >> >> # rsync -av --exclude '.zfs' /mnt/tank/docs-flore= nt/ /bench<br> >> >> [...]<br> >> >> sent 241,042,476,154 bytes=C2=A0 received 353,838 bytes= =C2=A0 81,806,492.45 bytes/sec<br> >> >> total size is 240,982,439,038=C2=A0 speedup is 1.00<br> >> >><br> >> >> # zfs get recordsize bench<br> >> >> NAME=C2=A0 =C2=A0PROPERTY=C2=A0 =C2=A0 VALUE=C2=A0 =C2=A0= SOURCE<br> >> >> bench=C2=A0 recordsize=C2=A0 128K=C2=A0 =C2=A0 =C2=A0defa= ult<br> >> >><br> >> >> # zpool list -v bench<br> >> >> NAME=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0SIZE=C2=A0 ALLOC=C2=A0 =C2=A0FREE<br> >> >> CKPOINT=C2=A0 EXPANDSZ=C2=A0 =C2=A0FRAG=C2=A0 =C2=A0 CAP= =C2=A0 DEDUP=C2=A0 =C2=A0 HEALTH=C2=A0 ALTROOT<br> >> >> bench=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A02.72T=C2=A0 =C2=A0226G=C2=A0 2.50T<br> >> >>=C2=A0 =C2=A0-=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0-=C2=A0 = =C2=A0 =C2=A00%=C2=A0 =C2=A0 =C2=A08%=C2=A0 1.00x=C2=A0 =C2=A0 ONLINE=C2=A0= -<br> >> >>=C2=A0 =C2=A0gptid/3c0f5cbc-b0ce-11ea-ab91-c8cbb8cc3ad4=C2= =A0 2.72T=C2=A0 =C2=A0226G=C2=A0 2.50T<br> >> >>=C2=A0 =C2=A0-=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0-=C2=A0 = =C2=A0 =C2=A00%=C2=A0 8.10%=C2=A0 =C2=A0 =C2=A0 -=C2=A0 =C2=A0 ONLINE<br> >> >><br> >> >> # zfs list bench<br> >> >> NAME=C2=A0 =C2=A0 USED=C2=A0 AVAIL=C2=A0 =C2=A0 =C2=A0REF= ER=C2=A0 MOUNTPOINT<br> >> >> bench=C2=A0 =C2=A0226G=C2=A0 2.41T=C2=A0 =C2=A0 =C2=A0 22= 6G=C2=A0 /bench<br> >> >><br> >> >> # zfs get all bench |egrep "(used|referenced|written= )"<br> >> >> bench=C2=A0 used=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0= =C2=A0 =C2=A0 =C2=A0 226G=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0-<br> >> >> bench=C2=A0 referenced=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 226G=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0-<br> >> >> bench=C2=A0 usedbysnapshots=C2=A0 =C2=A0 =C2=A0 =C2=A00B= =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0-<br> >> >> bench=C2=A0 usedbydataset=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0226G=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0-<br> >> >> bench=C2=A0 usedbychildren=C2=A0 =C2=A0 =C2=A0 =C2=A0 1.8= 0M=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 -<br> >> >> bench=C2=A0 usedbyrefreservation=C2=A0 0B=C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0-<br> >> >> bench=C2=A0 written=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0226G=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0-<br> >> >> bench=C2=A0 logicalused=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0= =C2=A0226G=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0-<br> >> >> bench=C2=A0 logicalreferenced=C2=A0 =C2=A0 =C2=A0226G=C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0-<br> >> >><br> >> >> # zdb -Lbbbs bench > zpool-bench-rcd128K.zdb<br> >> >><br> >> >><br> >> >><br> >> >> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D<br> >> >> B) 1M<br> >> >> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D<br> >> >><br> >> >> # zpool destroy bench<br> >> >> # zpool create -o ashift=3D12 bench<br> >> >> /dev/gptid/3c0f5cbc-b0ce-11ea-ab91-c8cbb8cc3ad4<br> >> >> # zfs set recordsize=3D1M bench<br> >> >><br> >> >> # rsync -av --exclude '.zfs' /mnt/tank/docs-flore= nt/ /bench<br> >> >> [...]<br> >> >> sent 241,042,476,154 bytes=C2=A0 received 353,830 bytes= =C2=A0 80,173,899.88 bytes/sec<br> >> >> total size is 240,982,439,038=C2=A0 speedup is 1.00<br> >> >><br> >> >> # zfs get recordsize bench<br> >> >> NAME=C2=A0 =C2=A0PROPERTY=C2=A0 =C2=A0 VALUE=C2=A0 =C2=A0= SOURCE<br> >> >> bench=C2=A0 recordsize=C2=A0 1M=C2=A0 =C2=A0 =C2=A0 =C2= =A0local<br> >> >><br> >> >> # zpool list -v bench<br> >> >> NAME=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0SIZE=C2=A0 ALLOC=C2=A0 =C2=A0FREE<br> >> >> CKPOINT=C2=A0 EXPANDSZ=C2=A0 =C2=A0FRAG=C2=A0 =C2=A0 CAP= =C2=A0 DEDUP=C2=A0 =C2=A0 HEALTH=C2=A0 ALTROOT<br> >> >> bench=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A02.72T=C2=A0 =C2=A0232G=C2=A0 2.49T<br> >> >>=C2=A0 =C2=A0-=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0-=C2=A0 = =C2=A0 =C2=A00%=C2=A0 =C2=A0 =C2=A08%=C2=A0 1.00x=C2=A0 =C2=A0 ONLINE=C2=A0= -<br> >> >>=C2=A0 =C2=A0gptid/3c0f5cbc-b0ce-11ea-ab91-c8cbb8cc3ad4=C2= =A0 2.72T=C2=A0 =C2=A0232G=C2=A0 2.49T<br> >> >>=C2=A0 =C2=A0-=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0-=C2=A0 = =C2=A0 =C2=A00%=C2=A0 8.32%=C2=A0 =C2=A0 =C2=A0 -=C2=A0 =C2=A0 ONLINE<br> >> >><br> >> >> # zfs list bench<br> >> >> NAME=C2=A0 =C2=A0 USED=C2=A0 AVAIL=C2=A0 =C2=A0 =C2=A0REF= ER=C2=A0 MOUNTPOINT<br> >> >> bench=C2=A0 =C2=A0232G=C2=A0 2.41T=C2=A0 =C2=A0 =C2=A0 23= 2G=C2=A0 /bench<br> >> >><br> >> >> # zfs get all bench |egrep "(used|referenced|written= )"<br> >> >> bench=C2=A0 used=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0= =C2=A0 =C2=A0 =C2=A0 232G=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0-<br> >> >> bench=C2=A0 referenced=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 232G=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0-<br> >> >> bench=C2=A0 usedbysnapshots=C2=A0 =C2=A0 =C2=A0 =C2=A00B= =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0-<br> >> >> bench=C2=A0 usedbydataset=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0232G=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0-<br> >> >> bench=C2=A0 usedbychildren=C2=A0 =C2=A0 =C2=A0 =C2=A0 1.9= 6M=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 -<br> >> >> bench=C2=A0 usedbyrefreservation=C2=A0 0B=C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0-<br> >> >> bench=C2=A0 written=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0232G=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0-<br> >> >> bench=C2=A0 logicalused=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0= =C2=A0232G=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0-<br> >> >> bench=C2=A0 logicalreferenced=C2=A0 =C2=A0 =C2=A0232G=C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0-<br> >> >><br> >> >> # zdb -Lbbbs bench > zpool-bench-rcd1M.zdb<br> >> >><br> >> >><br> >> >><br> >> >> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D<br> >> >> Notes:<br> >> >> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D<br> >> >><br> >> >> - the source dataset contains ~50% of pictures (raw files= and jpg),<br> >> >> and also some music, various archived documents, zip, vid= eos<br> >> >> - no change on the source dataset while testing (cf size = logged by resync)<br> >> >> - I repeated the tests twice (128K, then 1M, then 128K, t= hen 1M), and<br> >> >> same results<br> >> >> - probably not important here, but:<br> >> >> /dev/gptid/3c0f5cbc-b0ce-11ea-ab91-c8cbb8cc3ad4 is a Red = 3TB CMR<br> >> >> (WD30EFRX), and /mnt/tank/docs-florent/ is a 128K-records= ize dataset<br> >> >> on another zpool that I never tweaked except ashit=3D12 (= because using<br> >> >> the same model of Red 3TB)<br> >> >><br> >> >> # zfs --version<br> >> >> zfs-2.0.6-1<br> >> >> zfs-kmod-v2021120100-zfs_a8c7652<br> >> >><br> >> >> # uname -a<br> >> >> FreeBSD xxxxxxxxx 12.2-RELEASE-p11 FreeBSD 12.2-RELEASE-p= 11<br> >> >> 75566f060d4(HEAD) TRUENAS=C2=A0 amd64<br> </blockquote></div> --00000000000082918105d5dc68dc--
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