Re: cannot alloc 19968 bytes for inoinfo

From: Julian Elischer <julian_at_elischer.org>
Date: Thu, 02 Jun 2005 12:28:50 -0700
Bcc'd to some recipients. (you know who you are..)

Don Lewis wrote:

>On  2 Jun, Eric Anderson wrote:
>  
>
>>Don Lewis wrote:
>>    
>>
>>>On  1 Jun, Eric Anderson wrote:
>>>
>>>      
>>>
>>>>Andre Guibert de Bruet wrote:
>>>>
>>>>        
>>>>
>>>>>On Wed, 1 Jun 2005, Eric Anderson wrote:
>>>>>
>>>>>
>>>>>          
>>>>>
>>>>>>Don Lewis wrote:
>>>>>>
>>>>>>
>>>>>>            
>>>>>>
>>>>>>>On 31 May, Eric Anderson wrote:
>>>>>>>
>>>>>>>
>>>>>>>              
>>>>>>>
>>>>>>>>One of my filesystems won't fsck.  I'm not sure how to fix it, or 
>>>>>>>>what it's really trying to tell me.
>>>>>>>>
>>>>>>>># fsck -y /vol1
>>>>>>>>** /dev/da0s1d
>>>>>>>>** Last Mounted on /vol1
>>>>>>>>** Phase 1 - Check Blocks and Sizes
>>>>>>>>fsck_ufs: cannot alloc 19968 bytes for inoinfo
>>>>>>>>
>>>>>>>>df -i /vol1 output:
>>>>>>>>Filesystem  1K-blocks        Used    Avail Capacity  iused     ifree 
>>>>>>>>%iused  Mounted on
>>>>>>>>/dev/da0s1d 1891668564 1684163832 56171248    97% 55109756 189360002 
>>>>>>>>23% /vol1
>>>>>>>>
>>>>>>>>Any help would be very appreciated!
>>>>>>>>                
>>>>>>>>
>>>>>>>You're probably running into the default 512MB data size limit.  Try
>>>>>>>setting kern.maxdsiz to a larger value in /boot/loader.conf and
>>>>>>>rebooting.  I've got mine set to 1GB.
>>>>>>>   kern.maxdsiz="1073741824"
>>>>>>>              
>>>>>>>
>>>>>>Hmm - I don't seem to have that sysctl..  What would create it?
>>>>>>            
>>>>>>
>>>>>It's a loader tunable, not a sysctl variable. man 5 loader.conf
>>>>>          
>>>>>
>>>>Oh.. oops. :)   Ok, then I have it set correctly but it isn't helping 
>>>>me.  My fsck still dies the same way.  Looks like it's taking up about 
>>>>362MB memory (I have 1GB).  Any more ideas?
>>>>        
>>>>
>>>What does the shell limit command say about your datasize limit?  Your
>>>limit might have been cranked down in login.conf.
>>>      
>>>
>>I looked too early at the fsck. It appears to actually be going up to 
>>the 1GB limit now, and then bombing. It's now bombing at a different point:
>>
>># fsck -y /vol1
>>** /dev/da0s1d
>>** Last Mounted on /vol1
>>** Phase 1 - Check Blocks and Sizes
>>fsck_ufs: cannot increase directory list
>>
>>
>># limits
>>Resource limits (current):
>>   cputime          infinity secs
>>   filesize         infinity kb
>>   datasize          1048576 kb
>>   stacksize           65536 kb
>>   coredumpsize     infinity kb
>>   memoryuse        infinity kb
>>   memorylocked     infinity kb
>>   maxprocesses         7390
>>   openfiles           14781
>>   sbsize           infinity bytes
>>   vmemoryuse       infinity kb
>>
>>So I think I just need more RAM.. This is really a major ceiling for 
>>anyone that wants a somewhat large filesystem, or someone who needs a 
>>lot of inodes.  Is there maybe a different way to do the fsck that might 
>>take longer, but run in 'small' memory footprints like 1GB or less?  I 
>>know little to nothing about coding fsck tools or memory management, but 
>>I do know that there's always more ways to do something.  Just curious 
>>if there could be a 'lowmem' option for fsck that would utilize memory 
>>differently in order to fsck large fs's.
>>    
>>
>
>You can crank up datasize to be larger than RAM assuming that you have
>sufficient swap configured.  It'll just be slow as fsck starts paging.
>At some point on 32-bit architectures like the i386 you'll run into the
>address space limit, probably at 2-3GB.
>
>I think julian_at_ has mentioned having a version of fsck that uses
>external storage.  I would expect a substantial speed impact, and you
>would need at least one other file system mounted rw.
>  
>

exactly.
We haven't done this yet, however it's on our development
roadmap for the next generation of raids.
In our "back of the envelope" designs and calculations it
is hard to say conclusively  that it will be a lot slower. You do
the work in several passes of the disk where you never go 'backwards'..
instead, you write out "addresses of interest" that are behind
you to a "read this on the next pass" list that you write
out to the other storage.  The "next pass read" lists are sorted
in ram as much as possible before being written out
and then you do an on-disk "merge sort" on them as needed
to produce an "in-order" read list.

you keep doing this, producing some sorted output lists that detail such 
things as
block ranges in use etc. and in the end you reconcile all the output files
to produce the real bitmaps, find collisions, find ureferenced Inodes etc.
Onc eagain you put the output files out in chunks htat ar epre-sorted in 
RAM
and then do merge-sorts as needed on them to produce sorted output lists.
The output files would be sorted by different fields for different tests.
for example a list of referenced block ranges, sorted by start block,
quickly finds multiple inodes referencing the same blocks and quickly gives
you the correct bitmaps. A list of referenced inodes, sorted by inode 
number
gives you link counts and unreferenced inodes.. etc.etc.

In the current fsck the majority of time is spent waiting for the head to
rattle backwards and forwards as it follows links so it is hard to say 
without trying it
whether we will be slower than that if we only do forward passes..

(my guess is "yes, we'll be slower, but not by orders of magnitude, and 
definitly
a lot faster than a system that can't fsck it at all due to lack of RAM. :-)

Julian

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Received on Thu Jun 02 2005 - 17:28:51 UTC

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