[ale] ZFS on Linux

Ed Cashin ecashin at noserose.net
Tue Apr 2 10:11:02 EDT 2013


I believe Richard Elling mentioned in his March 2010 class that he
regularly sets up an unmounted dataset to reserve some space, and he warns
the client not to fill up the ZFS, but if they do, then he can come in and
delete the dataset to save the day.


On Mon, Apr 1, 2013 at 7:14 AM, Wolf Halton <wolf.halton at gmail.com> wrote:

> A gotcha on ZFS:
> If it ever fills up a drive array, for instance the backup process starts
> writing recursively, you can't remove anything, since it uses disk space to
> write a cache of what you delete.  You have to copy the files to a larger
> array and reformat your stuffed ZFS array.  Ask me how I know?
>
>
> On Sat, Mar 30, 2013 at 1:49 AM, gcs8 <gcsviii at gmail.com> wrote:
>
>> David, my whole rack takes under 6 amps to power, I am pretty good at
>> hardware design..
>>
>>
>> On Sat, Mar 30, 2013 at 12:11 AM, Jim Kinney <jim.kinney at gmail.com>wrote:
>>
>>> Heh, heh.
>>>
>>> Informatics research eats drive space like it's free.
>>>
>>> You should see the nifty new tape system that UPS delivered today.
>>>
>>> dual LTO6 with 48 slots. It will be managed by a head end connected over
>>> 10G ethernet to second server with 2 arrays (1 has 15 2TB drive and the
>>> other is 12 2TB drives.)
>>>
>>> The 16 4TB drive system actually has dual 2.5 SAS drives for OS drives
>>> plus the main 16 and a honkin' LTO6 tape system with 24 slots. This
>>> connected over a dedicated 10G ethernet to the main number cruncher with
>>> serious CPU and RAM and x16 2TB drives. There's an option to add an
>>> additional 12 drives in the back of the server.
>>>
>>> http://www.supermicro.com/products/chassis/3U/837/SC837E16-RJBOD1.cfm
>>>
>>>
>>> On Fri, Mar 29, 2013 at 10:41 PM, dev null zero two <
>>> dev.null.02 at gmail.com> wrote:
>>>
>>>> rainbow tables ofc :-)
>>>>
>>>> what sort of case are you using for that many hdds?
>>>>
>>>> Sent from my mobile. Please excuse the brevity, spelling, and
>>>> punctuation.
>>>> On Mar 29, 2013 10:36 PM, "David Tomaschik" <david at systemoverlord.com>
>>>> wrote:
>>>>
>>>>> I can only imagine the power bill for 20-30 hard drives & all the
>>>>> controllers and CPU needed to spin that all up.  (And unfortunately, I have
>>>>> good guesses as to what its used for.)
>>>>>
>>>>>
>>>>> On Fri, Mar 29, 2013 at 3:13 PM, gcs8 <gcsviii at gmail.com> wrote:
>>>>>
>>>>>> i run raidz2, if i could chang anything it would be adding SSD
>>>>>> caching and dual SSD ZIL.
>>>>>>
>>>>>>
>>>>>> On Fri, Mar 29, 2013 at 5:07 PM, Jim Kinney <jim.kinney at gmail.com>wrote:
>>>>>>
>>>>>>> That sounds encouraging. I'll have probably 2 arrays. One with 15
>>>>>>> 1TB data and a 2nd with 16 4TB SAS2. thinking raidz with a spare drive for
>>>>>>> each.
>>>>>>>  On Mar 29, 2013 4:43 PM, "gcs8" <gcsviii at gmail.com> wrote:
>>>>>>>
>>>>>>>> I run a 20 2TB disk array at home and have rather fond of ZFS, its
>>>>>>>> been stable for me for ~3 years now.
>>>>>>>>
>>>>>>>>
>>>>>>>> On Fri, Mar 29, 2013 at 3:10 PM, Ed Cashin <ecashin at noserose.net>wrote:
>>>>>>>>
>>>>>>>>> Thanks in advance for the notes you take.  I'm interested to hear
>>>>>>>>> what you find.
>>>>>>>>>
>>>>>>>>> By the way, work sent me to a Nexenta course in 2010 where I
>>>>>>>>> learned ZFS stuff from Richard Elling:
>>>>>>>>>
>>>>>>>>>   http://www.richardelling.com/
>>>>>>>>>
>>>>>>>>> ... and one thing that kept coming up is how users usually reach
>>>>>>>>> for the RAID-Z options when stripes of mirrors would perform better and
>>>>>>>>> offer more flexibility.  I thought that was notable.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> On Fri, Mar 29, 2013 at 2:44 PM, Jim Kinney <jim.kinney at gmail.com>wrote:
>>>>>>>>>
>>>>>>>>>> There was an update to this that just hit /.
>>>>>>>>>>
>>>>>>>>>> WooHoo!
>>>>>>>>>>
>>>>>>>>>> I have not used ZFS (minimal solaris experience) before but I
>>>>>>>>>> have a situation where raidz looks like a very good choice. An external 16
>>>>>>>>>> bay JBOD box hanging off a SAS HBA looks like a prime candidate. The big
>>>>>>>>>> issue for me is the support for native NFSv4 ACLs which solves some issues.
>>>>>>>>>>
>>>>>>>>>> As I go through this exercise, I'll keep some notes and maybe
>>>>>>>>>> look at a presentation on doing this.
>>>>>>>>>>
>>>>>>>>>> hints, gotcha's, are very welcome.
>>>>>>>>>>
>>>>>>>>>> I did find a pdf of the zfsadmin.pdf
>>>>>>>>>> http://pdfhome.org/zfsadmin.pdf
>>>>>>>>>>
>>>>>>>>>> --
>>>>>>>>>> --
>>>>>>>>>> James P. Kinney III
>>>>>>>>>> *
>>>>>>>>>> *Every time you stop a school, you will have to build a jail.
>>>>>>>>>> What you gain at one end you lose at the other. It's like feeding a dog on
>>>>>>>>>> his own tail. It won't fatten the dog.
>>>>>>>>>> - Speech 11/23/1900 Mark Twain
>>>>>>>>>> *
>>>>>>>>>> http://electjimkinney.org
>>>>>>>>>> http://heretothereideas.blogspot.com/
>>>>>>>>>> *
>>>>>>>>>> _______________________________________________
>>>>>>>>>> Ale mailing list
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>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> --
>>>>>>>>>   Ed Cashin <ecashin at noserose.net>
>>>>>>>>>   http://noserose.net/e/
>>>>>>>>>   http://www.coraid.com/
>>>>>>>>>
>>>>>>>>> _______________________________________________
>>>>>>>>> Ale mailing list
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>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> --
>>>>>>>> Charles Selfridge
>>>>>>>>
>>>>>>>> PBYC  IT director
>>>>>>>>
>>>>>>>> (404) 910-3409
>>>>>>>>
>>>>>>>> _______________________________________________
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>>>>>>>>
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>>>>>>
>>>>>>
>>>>>> --
>>>>>> Charles Selfridge
>>>>>>
>>>>>> PBYC  IT director
>>>>>>
>>>>>> (404) 910-3409
>>>>>>
>>>>>> _______________________________________________
>>>>>> Ale mailing list
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>>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> David Tomaschik
>>>>> OpenPGP: 0x5DEA789B
>>>>> http://systemoverlord.com
>>>>> david at systemoverlord.com
>>>>>
>>>>> _______________________________________________
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>>>>>
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>>>>
>>>
>>>
>>> --
>>> --
>>> James P. Kinney III
>>> *
>>> *Every time you stop a school, you will have to build a jail. What you
>>> gain at one end you lose at the other. It's like feeding a dog on his own
>>> tail. It won't fatten the dog.
>>> - Speech 11/23/1900 Mark Twain
>>> *
>>> http://electjimkinney.org
>>> http://heretothereideas.blogspot.com/
>>> *
>>>
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>>>
>>
>>
>> --
>> Charles Selfridge
>>
>> PBYC  IT director
>>
>> (404) 910-3409
>>
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>>
>
>
> --
> Wolf Halton
> This Apt Has Super Cow Powers - http://sourcefreedom.com
> Open-Source Software in Libraries - http://FOSS4Lib.org
> Advancing Libraries Together - http://LYRASIS.org
> Apache Open Office Developer wolfhalton at apache.org
>
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>


-- 
  Ed Cashin <ecashin at noserose.net>
  http://noserose.net/e/
  http://www.coraid.com/
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