ZFS: raid VS copies=n
Question: How does the ZFS option 'copies=n' and raid relate to and interact with each other? specifically recovery in the event of a failure. For example, is having three disks in a raid-1 configuration with copies=1 effectively the same as having three disks in a raid-0 with copies=3? Are the copies distributed uniformly across all drives in the pool, or concentrated, or what? What happens with configs like a raid-z2 with copies=2? Which / how many disks can you lose? (I'm aware that like a lot of other ZFS options copies=n doesn't have to be global to the entire pool / directory structure, but for the sake of simplicity let's assume it is in this case). __ it has a certain smooth-brained appeal ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: check variable content size in sh script
I say this from a FreeBSD context. It may entirely be possible that a Linux distro uses bash in /bin/sh Yes. For most (all?) linux distros as well as osx, /bin/sh is actually bash. When I say emulation mode I mean running a script with a #!/bin/sh header on a system that doesn't have a real copy of sh. Whatever shell ends up running the script is effectively emulating sh's environment, at least in my mind. Bash is well known for not complaining when you use bash-specific features in a script which uses a #!/bin/sh header. This trips up many a programmer and causes script failures on systems where sh is not actually bash in disguise. This is why I question some things as to whether they're *really* valid pure sh syntax and not something that just happens to work in whatever shell is pretending to be sh (which I thought was tcsh on this machine I just did that test on, but on second look maybe not). __ it has a certain smooth-brained appeal ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: Hot Swapping SATA drive?
1) Given a system running FreeBSD 9.1-RELEASE, is anything bad gonna happen if I insert a drive into this thing while the system is running? Assuming your board supports sata hotswap (too lazy to check) it'll be just fine. I've done this many times with the machine I'm messing with zfs on. Will I be able to mount partitions contained on the drive in question after I do so? y 2) Given a system running FreeBSD 9.1-RELEASE, is anything bad gonna happen if I remove a drive from this thing while the system is running, assuming that I have already properly umounted all relevant partitions first? No. On my test machine I've been yoinking drives without even any unmounting and it's just fine (up until I pull that last drive in my array and zfs shits the bed). Honestly, the only thing you have to worry about is if you're in there messing with cable ends that you don't accidentally touch the cable clip to something else on the board and short it out. 3) Assuming that I want to do this stuff, what BIOS options should I be setting or unsetting on the motherboard? You need the sata ports running in straight up pure ahci mode (as opposed to IDE mode or compatible or something that emulates old style parallel-ata). Be aware that Windows up through XP doesn't support ahci, so if you're dual booting an old system you'll have problems. You'll also almost certainly want to disable any motherboard-based raid options too, as they tend to be complete crap. sata vs esata esata is pin-identical to normal sata. The only difference is that esata has a more robust plug design meant to handle frequent [dis]connections and tighter electrical requirements in the cable for longer distances. As far as your board/OS is concerned, it's just another sata port. __ it has a certain smooth-brained appeal ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: check variable content size in sh script
However, if the OP wanted to actually truncate $FOO to 51
characters:
NEWFOO=$( echo $FOO | awk -v max=51 '{print substr($0,0,max)}' )
You don't need all that for a simple truncation/substring, you can do it
with a direct assignment:
newfoo=${foo:0:51}
The three params here are variable, start position and length.
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Re: check variable content size in sh script
newfoo=${foo:0:51}
That works for bash, not sh.
Ok granted, but I don't think that ${#foo} is straight sh either, so I
assumed things bash/tcsh/ksh/whatever accept when running in sh
emulation were ok.
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Re: Hot Swapping SATA drive?
You need the sata ports running in straight up pure ahci mode (as opposed to IDE mode or compatible or something that emulates old style parallel-ata). OK. Thanks Quartz,. I'll make it a point to check for that. The wording on different bios' can often be confusing. I've seen ahci mode referred to on one board as native mode but on a different system it's referred to as enhanced (where normal is emulation), and other oddisims. Double check your mobo manual and find the chapter that talks about it. You'll also almost certainly want to disable any motherboard-based raid options too, as they tend to be complete crap. OK. I never use RAID in any form anyway, so it probably is already disabled, but I'll make a point to double check. A word of warning: Not all boards do things *right*, so it pays to test. I've encountered systems where you get gpt checksum errors and stuff when ahci is on because the board masks part of the drive for its fake-raid stuff even if you have fake-raid supposedly turned off. __ it has a certain smooth-brained appeal ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: Hot Swapping SATA drive?
Be aware that Windows up through XP doesn't support ahci, There is a huge amount of information via a quick Google search that would seem to contradict your statements regarding WinXP and AHCI. Sorry, poor choice of wording. I meant earlier versions of Windows don't support achi *natively*. As your links suggest, you can sometimes find that your manufacturer will provide a driver that lets you fake out WinXP into being ok with your board's implementation of ahci (usually by emulating SCSI), but it's not a universal solution. __ it has a certain smooth-brained appeal ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: check variable content size in sh script
#foo works with sh Is it actually part of the official spec though is what I'm wondering, or is it a case of other shells not rejecting 'advanced' statements when running in emulation. At least FreeBSD's implementation of sh (which is ash, I think) supports the # functionality. The reason I say all this is that my copy of tcsh (on this not-freebsd machine) *doesn't* work with this when in sh emulation. __ it has a certain smooth-brained appeal ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: check variable content size in sh script
By default, there is no bash on FreeBSD, Right right... I know this, but forgot what list I was on :) It doesn't help that I always install bash first thing on any freebsd box or it get's installed automatically as part of pc-bsd anyway. __ it has a certain smooth-brained appeal ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: Youtube Flash Videos broken?
I can work around this by downloading the files with clive and watching with mplayer, but I'd like to make this work again. To be honest, this is really the best solution for all platforms, win/mac/bsd/etc. I don't have flash installed on any of my machines: I use a plugin that downloads the mp4 and auto opens it in a local video player. This always works, you can jump/rewind without constant buffering, you don't have to deal with ads, and you don't have to deal with flash maxing out your cpu for no reason. __ it has a certain smooth-brained appeal ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: OT: posix sh problem
I'd really like to have this working cleanly on FreeBSD without requiring any funky shells Define funky shell. Does it have to be straight up plain sh? Can it use csh or tcsh syntax? Does bash count as 'funky'? or using any temporary files. Do you mean manually created temp files? because some of the different ways of doing process substitution and redirection will automatically create temp files for you in the background and fail on an unwritable filesystem. __ it has a certain smooth-brained appeal ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: OT: posix sh problem
fail on an unwritable filesystem. ...By which I mean you can't create new files because your disk is completely full or you're booting from a ramdisk that's messed up, etc. __ it has a certain smooth-brained appeal ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: Recipie for CPU souffle'
You might want to confirm that your processor model requires a thermal pad and not grease. Then hunt some down and use it instead of thermal grease. I seem to recall they were somewhat difficult to locate a place from which to purchase. It's not that bad these days, search amazon or something for thermal pad and you'll get a bunch of results. Just make sure you get an actual flexible pad and not a polished copper shim, which are often sold under the same name. __ it has a certain smooth-brained appeal ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re:
Personally I'm using FreeBSD _exclusively_ (!) on the desktop since version 4.0, and I haven't missed _any_ common desktopy thing that is required for my daily work. I was referring to general intent when I wrote that. For example, bsd has poor support for things like sleep/suspend/hibernate. While desktops and laptops would certainly take advantage of those things, severs generally don't, so fixing it has traditionally been low priority. In contrast, linux has that working out of the box on almost all hardware. Likewise in my experience a number of other home-use things like laptop wifi are generally better supported under linux. A similar situation exists for software, especially non-business software and oddball utilities. On bsd you can usually find something to do what you need, but you'll often be limited to one or two choices, whereas with linux you might have half a dozen. (Whether all these packages are GOOD or not is a separate issue :) I'm not saying that bsd *can't* be used for a home desktop, it certainly can, but it was never aimed at the grandma+laptop market and the hardware support and software selection reflects that. But I don't hold that against bsd. You can't be all things to all people, bsd is very good for servers and linux is good for home use, and they each have their place. __ it has a certain smooth-brained appeal ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: Copying memstick image to a USB (flash/thumb) drive
I have filed the following PR: http://www.freebsd.org/cgi/query-pr.cgi?pr=177431 Er, don't take my word for law: I have *no* idea if 1M is a good idea for most systems, I'm not even sure if it's optimal for mine. I did a single test with three random values at different orders of magnitude and picked the fastest. I do think that 10k is probably way under the right value, but someone should do proper testing on a variety of hardware before changing all the docs. As for the conv=sync option, I'm not convinced it's necessary either way. I've dd'd zillions of images to various media over the years and have never specified a conv parameter and I've never had problems. I don't think modern systems really care what the end is padded with (provided nothing is corrupt of course). Someone with more experience would need to chime in on this. __ it has a certain smooth-brained appeal ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re:
I have a new computer with windows 8, which I hate with a passion. I don't play music and I don't do a lot of pictures. Basically I only search, some EBay and games. Can I replace win8 with BSD? [pc/free]bsd *can* be used as a desktop system, but it's really aimed more at servers... a lot of common desktopy things aren't covered well. Based on the wording of your question it sounds like you're new to non-windows systems. I'd suggest you look into some flavor of linux instead (eg; ubuntu or mint): they'll be geared more towards what you'd be looking for I think. __ it has a certain smooth-brained appeal ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: Where's the metadata?
The problem is that now, the Windows system seems to think that the size of the thing is only something like 24.2 Megabytes... *not* the actual size, which is vastly larger (16GB). but then at the last second I hesitate and decide to actually try to _understand_ what's going on here, really, for a change. By default, when looking with disks in explorer, windows will only mess with partitions (slices). In this case, your usb drive has a single partition just big enough to hold the installer, with the remainder of the drive being dead space. You need to delete this partition and create a new one that spans the entire size of the drive. Unfortunately, windows doesn't make this as easy as it should be. You'll need to open your control panel - administrative tools - computer management - disk management So now I'm reading the man page for glabel(8) glabel is totally not related to your problem at all. glabel is for when you want to refer to disks via a user created identifier string when you can't rely on the device id. P.P.S. So what _is_ the best tool for just simply taking some sort of drive... like a USB flash drive, or any other kind of drive for that matter... and returning it to it's actual size? Use a real partitioning program as opposed to the crap built into the windows right-click menu. On freebsd, this would be 'gpart'. __ it has a certain smooth-brained appeal ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: Where's the metadata?
Did you try using fdisk? Don't use fdisk, it's waay out of date, doesn't work with a lot of modern large drives, and has horribly arcane syntax. Modern versions of gpart support MBR, so there's basically no reason to suffer through fdisk anymore. __ it has a certain smooth-brained appeal ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: OT: The future of USENET?
Is USENET coming to its end? Yes, for better or worse. It's been a slow downward spiral since the late 90's. I can't speak for other countries, but in the US the majority of ISPs started dropping access as a cost cutting measure since your average layman didn't really understand or use it. Younger generations in turn never knew it existed and ended up reinventing most of the functionality with web forums. Not helping matters is that, due to a couple isolated cases, the news media ignorantly view usenet as a haven for child porn and pirate movies, so there's increasing clamor to shut it down. There were a few 3rd party companies here and there that offered dedicated access, but most of them have closed up shop by this point due to social/political pressure. __ it has a certain smooth-brained appeal ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: Copying memstick image to a USB (flash/thumb) drive
Why exactly is the bs=10240 is there? Wouldn't the default of 512 do just as well? Modern systems can read and write far more than 512 bytes per operation. Sticking with 512 would work perfectly fine, but you'd be imposing an unnecessary bottleneck and the copy would be a lot slower overall. Whether 10K is optimal or not depends on the exact hardware you're messing with (it looks pretty low to me, I'd suggest more like 1M). __ it has a certain smooth-brained appeal ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
ZFS question
I'm experiencing fatal issues with pools hanging my machine requiring a hard-reset. I'm new to freebsd and these mailing lists in particular, is this the place to ask for help? __ it has a certain smooth-brained appeal ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: ZFS question
Several people, including me, have an issue like this with 9.1. Your best bet is to try 9.0. Hmm... interesting. Is there any consensus as to what's going on? Before anyone jumps to conclusions though, lemme just post the whole issue so we're on the same page (apologizes if it turns out this isn't the right mailing list for this): I have a raidz2 comprised of six sata drives connected via my motherboard's intel southbridge sata ports. All of the bios raid options are disabled and the drives are in straight ahci mode (hotswap enabled). The system (accounts, home dir, etc) is installed on a separate 7th drive formatted as normal ufs, connected to a separate non-intel motherboard port. As part of my initial stress testing, I'm simulating failures by popping the sata cable to various drives in the 6x pool. If I pop two drives, the pool goes into 'degraded' mode and everything works as expected. I can zero and replace the drives, etc, no problem. However, when I pop a third drive, the machine becomes VERY unstable. I can nose around the boot drive just fine, but anything involving i/o that so much as sneezes in the general direction of the pool hangs the machine. Once this happens I can log in via ssh, but that's pretty much it. I've reinstalled and tested this over a dozen times, and it's perfectly repeatable: `ls` the dir where the pool is mounted? hang. I'm already in the dir, and try to `cd` back to my home dir? hang. zpool destroy? hang. zpool replace? hang. zpool history? hang. shutdown -r now? gets halfway through, then hang. reboot -q? same as shutdown. The machine never recovers (at least, not inside 35 minutes, which is the most I'm willing to wait). Reconnecting the drives has no effect. My only option is to hard reset the machine with the front panel button. Googling for info suggested I try changing the pool's failmode setting from wait to continue, but that doesn't appear to make any difference. For reference, this is a virgin 9.1-release installed off the dvd image with no ports or packages or any extra anything. I don't think I'm doing anything wrong procedure wise. I fully understand and accept that a raidz2 with three dead drives is toast, but I will NOT accept having it take down the rest of the machine with it. As it stands, I can't even reliably look at what state the pool is in. I can't even nuke the pool and start over without taking the whole machine offline. __ it has a certain smooth-brained appeal ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: ZFS question
1. freebsd-fs is the proper list for filesystem-oriented questions of
this sort, especially for ZFS.
Ok, I'm assuming I should subscribe to that list and post there then?
2. The issue you've described is experienced by some, and **not**
experienced by even more/just as many, so please keep that in mind.
Well, that's a given. Presumably if zfs was flat out totally broken, 9.x
wouldn't have been released or I would've already found a million pages
about this via google. I'm assuming my problem is a corner case and
there might've been a bug/regression, or I fundamentally don't
understand how this works.
3. You haven't provided any useful details, even in your follow-up post
here:
I got the impression that there wasn't a lot of overlap between the
mailing lists and the forums, so I wanted to post in both simultaneously.
- Contents of /boot/loader.conf
- Contents of /etc/sysctl.conf
- Output from zpool get all
- Output from zfs get all
- Output from sysctl vfs.zfs kstat.zfs
I'm running a *virgin* 9.1 with no installed software or modifications
of any kind (past setting up a non-root user). All of these will be at
their install defaults (with the possible exception of the failmode
setting, but that didn't help when I tried it the first time, so I
didn't bother during later re-installs).
- Output from zpool status
There isn't a lot of detail to be had here after I pop the 3rd
drive, zfs/zpool commands almost always cause the system to hang, so I'm
not sure if I can get anything out of them. Prior to the hang it will
just tell you I have a six-drive raidz2 with two of the drives
removed, so I'm not sure how that will be terribly useful.
I can tell you though that I'm creating the array with the following
command:
zpool create -f array raidz2 ada{2,3,4,5,6,7}
There are eight drives in the machine at the moment, and I'm not messing
with partitions yet because I don't want to complicate things. (I will
eventually be going that route though as the controller tends to
renumber drives in a first-come-first-serve order that makes some things
difficult).
- Output from dmesg (probably the most important)
When? ie; right after boot, or after I've hot plugged a few drives, or
yanked them, or created a pool, or what?
I particularly tend to assist with disk-level problems,
This machine is using a pile of spare seagate 250gb drives, if that
makes any difference.
By rolling back, if there is an issue, you're
effectively ensuring it'll never get investigated or fixed,
That's why I asked for clarification, to see if it was a known
regression in 9.1 or something similar.
or don't have the
time/cycles/interest to help track it down,
I have plenty of all that, for better or worse :)
that's perfectly okay too:
my recommendation is to go back to UFS (there's no shame in that).
At the risk of being flamed off the list, I'll switch to debian if it
comes to that. I use freebsd exclusively for zfs.
Else, as always, I strongly recommend running stable/9 (keep reading).
My problem with tracking -stable is the relative volatility. If I'm
trying to debug a problem it's not always easy or possible to keep
consistent/known versions of things. With -release I know exactly what
I'm getting and it cuts out a lot of variables.
just recently (~5 days ago)
MFC'd an Illumos ZFS feature solely to help debug/troubleshoot this
exact type of situation: introduction of the ZFS deadmean thread.
Yes, I already discovered this from various solaris threads I encountered.
The purpose of this feature (enabled by default) is to induce a kernel
panic when ZFS I/O stalls/hangs
This doesn't really help my situation though. If I wanted a panic I'd
just set failmode=panic.
All that's assuming that the issue truly is ZFS waiting for I/O and not
something else
Well, everything I've read so far indicates that zfs has issues when
dealing with un-writable pools, so I assume that's what's going on here.
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