While this isn''t causing me any problems, I''m curious as to why this is happening...: $ dd if=/dev/random of=ob bs=128k count=1 && while true> do > ls -s ob > sleep 1 > done0+1 records in 0+1 records out ?? 1 ob ?? 1 ob ?? 1 ob ?? 1 ob ?? 1 ob ?? 1 ob ?? 1 ob ?? 1 ob ?? 1 ob ?? 1 ob ?? 1 ob ?? 1 ob ?? 1 ob ?? 1 ob ?? 1 ob ?? 1 ob ?? 1 ob ?? 1 ob ?? 1 ob ?? 1 ob ?? 1 ob ?? 1 ob ?? 1 ob ?? 1 ob ?? 1 ob ?? 1 ob ?? 1 ob ?? 1 ob ?? 4 ob?? <---- changes here ?? 4 ob ?? 4 ob ^C $ ls -l ob -rw-r--r--?? 1 justin staff?????? 1040 Aug? 3 09:28 ob I was expecting the ''1'', since this is a zfs with recordsize=128k. Not sure I understand the ''4'', or why it happens ~30s later.? Can anyone distribute clue in my direction? s10u10, running 144488-06 KU. zfs is v4, pool is v22. cheers, --justin -bash-3.00$
On 08/03/2012 03:18 PM, Justin Stringfellow wrote:> While this isn''t causing me any problems, I''m curious as to why this is happening...: > > > > $ dd if=/dev/random of=ob bs=128k count=1 && while trueCan you check whether this happens from /dev/urandom as well? -- Saso
2012-08-03 17:18, Justin Stringfellow ?????:> While this isn''t causing me any problems, I''m curious as to why this is happening...: > > > > $ dd if=/dev/random of=ob bs=128k count=1 && while true >> do >> ls -s ob >> sleep 1 >> done > 0+1 records in > 0+1 records out > 1 ob...> I was expecting the ''1'', since this is a zfs with recordsize=128k. Not sure I understand the ''4'', or why it happens ~30s later. Can anyone distribute clue in my direction? > > > s10u10, running 144488-06 KU. zfs is v4, pool is v22.I think for the cleanness of the experiment, you should also include "sync" after the dd''s, to actually commit your file to the pool. What is the pool''s redundancy setting? I am not sure what "ls -s" actually accounts for file''s FS-block usage, but I wonder if it might include metadata (relevant pieces of the block pointer tree individual to the file). Also check if the disk usage reported by "du -k ob" varies similarly, for the fun of it? //Jim
>Can you check whether this happens from /dev/urandom as well?It does: finsdb137 at root> dd if=/dev/urandom of=oub bs=128k count=1 && while true> do > ls -s oub > sleep 1 > done0+1 records in 0+1 records out ?? 1 oub ?? 1 oub ?? 1 oub ?? 1 oub ?? 1 oub ?? 4 oub ?? 4 oub ?? 4 oub ?? 4 oub ?? 4 oub
> I think for the cleanness of the experiment, you should also include"sync" after the dd''s, to actually commit your file to the pool. OK that ''fixes'' it: finsdb137 at root> dd if=/dev/random of=ob bs=128k count=1 && sync && while true> do > ls -s ob > sleep 1 > done0+1 records in 0+1 records out ?? 4 ob ?? 4 ob ?? 4 ob .. etc. I guess I knew this had something to do with stuff being flushed to disk, I don''t know why I didn''t think of it myself.> What is the pool''s redundancy setting?copies=1. Full zfs get below, but in short, it''s a basic mirrored root with default settings. Hmm, maybe I should mirror root with copies=2.....??? ;)> I am not sure what "ls -s" actually accounts for file''s FS-blockusage, but I wonder if it might include metadata (relevant pieces of the block pointer tree individual to the file). Also check if the disk usage reported by "du -k ob" varies similarly, for the fun of it? Yes, it varies too. finsdb137 at root> dd if=/dev/random of=ob bs=128k count=1 && while true> do > ls -s ob > du -k ob > sleep 1 > done0+1 records in 0+1 records out ?? 1 ob 0?????? ob ?? 1 ob 0?????? ob ?? 1 ob 0?????? ob ?? 1 ob 0?????? ob ?? 4 ob 2?????? ob ?? 4 ob 2?????? ob ?? 4 ob 2?????? ob ?? 4 ob 2?????? ob ?? 4 ob 2?????? ob finsdb137 at root> zfs get all rpool/ROOT/s10s_u9wos_14a NAME?????????????????????? PROPERTY????????????? VALUE????????????????? SOURCE rpool/ROOT/s10s_u9wos_14a? type????????????????? filesystem???????????? - rpool/ROOT/s10s_u9wos_14a? creation????????????? Tue Mar? 1 15:09 2011? - rpool/ROOT/s10s_u9wos_14a? used????????????????? 20.6G????????????????? - rpool/ROOT/s10s_u9wos_14a? available???????????? 37.0G????????????????? - rpool/ROOT/s10s_u9wos_14a? referenced??????????? 20.6G????????????????? - rpool/ROOT/s10s_u9wos_14a? compressratio???????? 1.00x????????????????? - rpool/ROOT/s10s_u9wos_14a? mounted?????????????? yes??????????????????? - rpool/ROOT/s10s_u9wos_14a? quota???????????????? none?????????????????? default rpool/ROOT/s10s_u9wos_14a? reservation?????????? none?????????????????? default rpool/ROOT/s10s_u9wos_14a? recordsize??????????? 128K?????????????????? default rpool/ROOT/s10s_u9wos_14a? mountpoint??????????? /????????????????????? local rpool/ROOT/s10s_u9wos_14a? sharenfs????????????? off??????????????????? default rpool/ROOT/s10s_u9wos_14a? checksum????????????? on???????????????????? default rpool/ROOT/s10s_u9wos_14a? compression?????????? off??????????????????? default rpool/ROOT/s10s_u9wos_14a? atime???????????????? on???????????????????? default rpool/ROOT/s10s_u9wos_14a? devices?????????????? on???????????????????? default rpool/ROOT/s10s_u9wos_14a? exec????????????????? on???????????????????? default rpool/ROOT/s10s_u9wos_14a? setuid??????????????? on???????????????????? default rpool/ROOT/s10s_u9wos_14a? readonly????????????? off??????????????????? default rpool/ROOT/s10s_u9wos_14a? zoned???????????????? off??????????????????? default rpool/ROOT/s10s_u9wos_14a? snapdir?????????????? hidden???????????????? default rpool/ROOT/s10s_u9wos_14a? aclmode?????????????? groupmask????????????? default rpool/ROOT/s10s_u9wos_14a? aclinherit??????????? restricted???????????? default rpool/ROOT/s10s_u9wos_14a? canmount????????????? noauto???????????????? local rpool/ROOT/s10s_u9wos_14a? shareiscsi??????????? off??????????????????? default rpool/ROOT/s10s_u9wos_14a? xattr???????????????? on???????????????????? default rpool/ROOT/s10s_u9wos_14a? copies??????????????? 1????????????????????? default rpool/ROOT/s10s_u9wos_14a? version?????????????? 3????????????????????? - rpool/ROOT/s10s_u9wos_14a? utf8only????????????? off??????????????????? - rpool/ROOT/s10s_u9wos_14a? normalization???????? none?????????????????? - rpool/ROOT/s10s_u9wos_14a? casesensitivity?????? sensitive????????????? - rpool/ROOT/s10s_u9wos_14a? vscan???????????????? off??????????????????? default rpool/ROOT/s10s_u9wos_14a? nbmand??????????????? off??????????????????? default rpool/ROOT/s10s_u9wos_14a? sharesmb????????????? off??????????????????? default rpool/ROOT/s10s_u9wos_14a? refquota????????????? none?????????????????? default rpool/ROOT/s10s_u9wos_14a? refreservation??????? none?????????????????? default rpool/ROOT/s10s_u9wos_14a? primarycache????????? all??????????????????? default rpool/ROOT/s10s_u9wos_14a? secondarycache??????? all??????????????????? default rpool/ROOT/s10s_u9wos_14a? usedbysnapshots?????? 0????????????????????? - rpool/ROOT/s10s_u9wos_14a? usedbydataset???????? 20.6G????????????????? - rpool/ROOT/s10s_u9wos_14a? usedbychildren??????? 0????????????????????? - rpool/ROOT/s10s_u9wos_14a? usedbyrefreservation? 0????????????????????? - rpool/ROOT/s10s_u9wos_14a? logbias?????????????? latency??????????????? default