On Thu, Jun 21, 2018 at 1:19 PM, Eric Sandeen <sandeen@xxxxxxxxxxx> wrote: > > > On 6/21/18 2:15 PM, Luis R. Rodriguez wrote: >> On Tue, Jun 19, 2018 at 02:21:15PM -0500, Eric Sandeen wrote: >>> On 6/19/18 11:18 AM, Darrick J. Wong wrote: >>>> On Tue, Jun 19, 2018 at 02:27:29PM +0200, swadmin - levigo.de wrote: >>>>> Hi @all >>>>> I have a problem with mounting a large XFS filesystem which takes about >>>>> 8-10 minutes. >>>>> >>>>> >>>>> >>>>> :~# df -h /graylog_data >>>>> Filesystem Size Used Avail Use% Mounted on >>>>> /dev/mapper/vgdata-graylog_data 11T 5.0T 5.1T 50% /graylog_data >>>>> >>>>> ---- >>>>> >>>>> :~# xfs_info /dev/mapper/vgdata-graylog_data >>>>> meta-data=/dev/mapper/vgdata-graylog_data isize=512 agcount=40805, >>>>> agsize=65792 blks >>>> >>>> 41,000 AGs is a lot of metadata to load. Did someone growfs a 1G fs >>>> into a 11T fs? >>> >>> <answer: yes, they did> >>> >>> Let me state that a little more clearly: this is a badly mis-administered >>> filesystem; 40805 x 256MB AGs is nearly unusable, as you've seen. >>> >>> If at all possible I would start over with a rationally-created filesystem >>> and migrate the data. >> >> Considering *a lot* of folks may typically follow the above "trap", wouldn't it >> be wise for userspace to complain or warn when the user may want to do >> something stupid like this? Otherwise I cannot see how we could possibly >> conceive that this is badly administered filesystem. > > Fair point, though I'm not sure where such a warning would go. growfs? > I'm not a big fan of the "you asked for something unusual, continue [y/N]?" > type prompts. > > To people who know how xfs is laid out it's "obvious" but it's not fair to > assume every admin knows this, you're right. So calling it mis-administered > was a bit harsh. > The extreme case is interesting to me, but even more interesting are the intermediate cases. Is it straightforward to establish a hard and fast threshold? i.e. do not growfs more than 1000% from original size? Do not growfs more than X times? Or is it a linear relationship between performance loss and each additional growfs? -- Chris Murphy -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
