[Lustre-discuss] It gives error "no space left" while lustre still have spaces left.

[Brock Palen]

If I understand right when you use 'setstripe -c -1'  lustre will try  
to evenly spread the data of a file over all OST's.

Because one of yours gets full, the file can nolonger be added to.   
Lustre does not fall back to using fewer stripes as most users say  
'use more stripes'  for a reason.  Lustre should not ignore this (and  
doesn't).

I don't know how you would work around a this,  A "use every stripe  
you can till its out of space"  I don't think exists.

Brock Palen
www.umich.edu/~brockp
Center for Advanced Computing
brockp at umich.edu
(734)936-1985



On Aug 21, 2008, at 12:13 AM, /* Chris */ wrote:
> Hi, all,
>
> I got a problem when I testing lustre-1.6.5.1 on CentOS-5.2.
> I have four machines(PCs), they are MGS co-located with MDT, OSS-1,  
> OSS-2 and CLT.
> OSS-1 have two disks which are formatted as ost01(40GB) and ost02 
> (15GB).
> OSS-2 have two disks which are formatted as ost03(23GB) and ost04 
> (5GB).
>
> At first, I reformat the MGS/MDT and mount it to /mnt/ as follow:
> [root at MGS ~]# mkfs.lustre --reformat --fsname=testfs --mgs --mdt / 
> dev/hdb
> [root at MGS ~]# mount -t lustre /dev/hdb /mnt/mgs
>
> Second, I reformat OSTs and mount it to /mnt as follow:
> [root at OSS-1 ~]# mkfs.lustre --reformat --fsname=testfs --ost -- 
> mgsnode=MGS at tcp /dev/hdc
> [root at OSS-1 ~]# mkfs.lustre --reformat --fsname=testfs --ost -- 
> mgsnode=MGS at tcp /dev/hdd
> [root at OSS-1 ~]# mount -t lustre /dev/hdc /mnt/ost01
> [root at OSS-1 ~]# mount -t lustre /dev/hdd /mnt/ost02
>
> [root at OSS-2 ~]# mkfs.lustre --reformat --fsname=testfs --ost -- 
> mgsnode=MGS at tcp /dev/hdc
> [root at OSS-2 ~]# mkfs.lustre --reformat --fsname=testfs --ost -- 
> mgsnode=MGS at tcp /dev/hdd
> [root at OSS-2 ~]# mount -t lustre /dev/hdc /mnt/ost03
> [root at OSS-2 ~]# mount -t lustre /dev/hdd /mnt/ost04
>
> Third, I mounted lustre file system at CLT like this:
> [root at CLT ~] # mount -t lustre MGS at tcp:/testfs /mnt/lfs
> [root at CLT mnt]# df -h
> Filesystem              Capacity  Used Available Use% Mounted on:
> /dev/mapper/VolGroup00-LogVol00 4.3G  1.9G  2.2G  46% /
> /dev/hda1                   99M   67M   28M  72% /boot
> tmpfs                        252M     0    252M   0% /dev/shm
> MGS at tcp:/testfs           82G  1.6G     77G   2% /mnt/lfs
> Fourth, I try to use "lfs" command to set stripe parameters at CLT.
> [root at CLT mnt]# lfs setstripe lfs -s 8m -c -1
>
> Fifth, I use "dd" command to test lustre file system.
> Then, it gives error "no space left" since just ost04(5GB) get full.
>
> [root at CLT lfs]# dd if=/dev/zero of=testfile001 bs=128M count=24
> 24+0 records in
> 24+0 records out
> 3221225472 bytes (3.2 GB) copied，164.585 seconds，19.6 MB/s
> [root at CLT lfs]# dd if=/dev/zero of=testfile002 bs=128M count=24
> 24+0 records in
> 24+0 records out
> 3221225472 bytes (3.2 GB) copied，164.836 seconds，19.5 MB/s
> [root at CLT lfs]# dd if=/dev/zero of=testfile003 bs=128M count=48
> 48+0 records in
> 48+0 records out
> 6442450944 bytes (6.4 GB) copied，383.2 seconds，16.8 MB/s
> [root at CLT lfs]# dd if=/dev/zero of=testfile004 bs=128M count=48
> dd: write error: ‘testfile004’: No space left on this device.
> 47+0 records in
> 46+0 records out
> 6301048832 bytes (6.3 GB) copied，418.321 秒，15.1 MB/s
>
> [root at CLT lfs]# df -h
> Filesystem              Capacity  Used Available Use% Mounted on
> /dev/mapper/VolGroup00-LogVol00  4.3G  1.9G  2.2G  46% /
> /dev/hda1                    99M   67M   28M  72% /boot
> tmpfs                        252M     0     252M    0% /dev/shm
> MGS at tcp:/testfs        82G   20G     59G  25% /mnt/lfs
> [root at CLT lfs]# lfs df
>                UUID                 1K-blocks      Used Available   
> Use% Mounted on
> testfs-MDT0000_UUID    2752272    127844   2467144    4% /mnt/lfs 
> [MDT:0]
> testfs-OST0000_UUID   41284928   5145080  34042632   12% /mnt/lfs 
> [OST:0]
> testfs-OST0001_UUID   15481840   5134432   9560912   33% /mnt/lfs 
> [OST:1]
> testfs-OST0002_UUID   23738812   5141040  17391848   21% /mnt/lfs 
> [OST:2]
> testfs-OST0003_UUID    5160576   4898364         4   94% /mnt/lfs 
> [OST:3]
>
> filesystem summary:   85666156  20318916  60995396   23% /mnt/lfs
> I have no idea about this error.
> Is there anyone could tell me about that how to config lustre to  
> avoid this error?
> didn't Lustre put file into the OSTs which still have free spaces  
> instead of those full ones ?
>
>
> Regards,
>
> Chris
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