Date: Mon, 3 Oct 2016 12:35:08 +0300 From: Daniel Braniss <danny@cs.huji.ac.il> To: "O. Hartmann" <ohartman@zedat.fu-berlin.de> Cc: Allan Jude <allanjude@freebsd.org>, freebsd-current@freebsd.org Subject: Re: ZFS - Abyssal slow on copying Message-ID: <28DF6F19-A97F-4029-9D55-77E14B38B45D@cs.huji.ac.il> In-Reply-To: <20161003113050.0f1b09bd.ohartman@zedat.fu-berlin.de> References: <20161002212504.2d782002.ohartman@zedat.fu-berlin.de> <ae0af48b-b462-876e-4139-a6fcc2836794@freebsd.org> <20161003113050.0f1b09bd.ohartman@zedat.fu-berlin.de>
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> On 3 Oct 2016, at 12:30 PM, O. Hartmann <ohartman@zedat.fu-berlin.de> wrote: > > Am Sun, 2 Oct 2016 15:30:41 -0400 > Allan Jude <allanjude@freebsd.org <mailto:allanjude@freebsd.org>> schrieb: > >> On 2016-10-02 15:25, O. Hartmann wrote: >>> >>> Running 12-CURRENT (FreeBSD 12.0-CURRENT #32 r306579: Sun Oct 2 09:34:50 CEST 2016 >>> ), I have a NanoBSD setup which creates an image for a router device. >>> >>> The problem I face is related to ZFS. The system has a system's SSD (Samsung 850 Pro, >>> 256GB) which has an UFS filesystem. Aditionally, I have also a backup and a data HDD, >>> both WD, one 3 TB WD RED Pro, on 4 TB WD RED (the backup device). Both the sources for >>> the NanoBSD and the object tree as well as the NANO_WORLDDIR are residing on the 3 TB >>> data drive. >>> >>> The box itself has 8 GB RAM. When it comes to create the memory disk, which is ~ 1,3 >>> GB in size, the NanoBSD script starts creating the memory disk and then installing >>> world into this memory disk. And this part is a kind of abyssal in terms of the speed. >>> >>> The drive sounds like hell, the heads are moving rapidly. The copy speed is incredibly >>> slow compared to another box I usually use in the lab with UFS filesystem only >>> (different type of HDD). >>> >>> The whole stuff the nanbsd is installed from and to is on a separate ZFS partition, >>> but in the same pool as everything else. When I first setup the new partitions, I >>> switched on deduplication, but I quickly deactivated it, because it had a tremendous >>> impact on the working speed and memory consumption on that box. But something seems >>> not right since then - as I initially described, the copy/initialisation >>> speed/bandwith is abyssal. Well, I also fear that I did something wrong when I firt >>> initialised the HDD - there is this 125bytes/4k block discussion and I do not know >>> how to check whether I'm affected to that or not (or even causing the problems) and >>> how to check whether DEDUPLICATION is definitely OFF (apart from the usual stuff list >>> features via "zfs get all"). >>> >>> As an example: the nanbosd script takes ~ 1 minute to copy /boot/loader from source to >>> memory disk and the HDD makes sounds like hell and close to loosing the r/w heads. On >>> other boxes this task is done in a blink of an eye ... >>> >>> Thanks for your patience, >>> >>> Regards, >>> oh >>> >> >> Turning deduplication off, only stops new blocks from being >> deduplicated. Any data written while deduplication was on, are still >> deduplicated. You would need to zfs send | zfs recv, or >> backup/destroy/restore to get the data back to normal. >> >> If the drive is making that much noise, have you considered that the >> drive might be failing? >> > > Hello. > > Might there be any hint I can investigate on that ZFS partition showing me that the > particular partition is still doing deduplication? If I wouldn't know that I switch > dedup on and later off, I would blame the OS instead. So, for further forensik analysis > in the future, it would be nice to know how to look at it - if it is doable via simple > checking the features of the ZFS partition ... > > Thanks, > oh not really an answer, but zpool has a nice command: history, it sometimes helps to find what and when nfs commands where given. danny
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