18 Jul
2023
18 Jul
'23
5:42 p.m.
Dan,
Ok, I've discovered a few more things.
None of the bucket index objects show up as type 'olh' in the bi list they are all
'plain'. Since my objects begin with "<80>0_", this appears to be
abucket log index as per:
static std::string bucket_index_prefixes
in cls_rgw.cc.
One of these omapkey objects is being created every few minutes on a particular shard on
several buckets. This is what is causing the omap object warning. The keys and values
therein appear to be valid, but there are some that don't make sense as they have a
'key' entry of 26 bytes., that appear to have the same format as the omap object
itself: <80>0_0000xxxxxxx.y. There are 1000s of these 26 byte keys....
My users do create 1000s of small objects that they eventually delete. But this continues.
Any ideas?
-Chris
On Tuesday, July 18, 2023 at 12:14:18 PM MDT, Dan van der Ster
<dan.vanderster(a)clyso.com> wrote:
Hi Chris,
Those objects are in the so called "ugly namespace" of the rgw, used to prefix
special bucket index entries.
// No UTF-8 character can begin with 0x80, so this is a safe indicator
// of a special bucket-index entry for the first byte. Note: although
// it has no impact, the 2nd, 3rd, or 4th byte of a UTF-8 character
// may be 0x80.
#define BI_PREFIX_CHAR 0x80
You can use --omap-key-file and some sed magic to interact with those keys, e.g. like this
example from my archives [1].(In my example I needed to remove orphaned olh entries -- in
your case you can generate uglykeys.txt in whichever way is meaningful for your
situation.)
BTW, to be clear, I'm not suggesting you blindly delete those keys. You would need to
confirm that they are not needed by a current bucket instance before deleting, lest some
index get corrupted.
Cheers, Dan______________________________________________________
Clyso GmbH | Ceph Support and Consulting | https://www.clyso.com
[1]
# radosgw-admin bi list --bucket=xxx --shard-id=0 >
xxx.bilist.0
# cat xxx.bilist.0 | jq -r '.[]|select(.type=="olh" and
.entry.key.name=="") | .idx' > uglykeys.txt
# head -n2 uglykeys.txt
�1001_00/2a/002a985cc73a01ce738da460b990e9b2fa849eb4411efb0a4598876c2859d444/2018_12_11/2893439/3390300/metadata.gz
�1001_02/5f/025f8e0fc8234530d6ae7302adf682509f0f7fb68666391122e16d00bd7107e3/2018_11_14/2625203/3034777/metadata.gz
# cat do_remove.sh
# usage: "bash do_remove.sh | sh -x"
while read f;
do
echo -n $f | sed 's/^.1001_/echo -n -e \\\\x801001_/'; echo ' > mykey
&& rados rmomapkey -p default.rgw.buckets.index
.dir.zone.bucketid.xx.indexshardnumber --omap-key-file mykey';
done < uglykeys.txt
On Tue, Jul 18, 2023 at 9:27 AM Christopher Durham <caduceus42(a)aol.com> wrote:
Hi,
I am using ceph 17.2.6 on rocky linux 8.
I got a large omap object warning today.
Ok, So I tracked it down to a shard for a bucket in the index pool of an s3 pool.
However, when lisitng the omapkeys with:
# rados -p pool.index listomapkeys .dir.zone.bucketid.xx.indexshardnumber
it is clear that the problem is caused by many omapkeys with the following name format:
<80>0_00004771163.3444695458.6
A hex dump of the output of the listomapkeys command above indicates that the first
'character' is indeed hex 80, but as there is no equivalent ascii for hex 80, I am
not sure how to 'get at' those keys to see the values, delete them, etc. The index
keys not of the format above appear to be fine, indicating s3 object names as expected.
The rest of the index shards for the bucket are reasonable and have less than
osd_deep_scrub_large_omap_object_key_threshold index objects , and the overall total of
objects in the bucket is way less than
osd_deep_scrub_large_omap_object_key_threshold*num_shards.
These weird objects seem to be created occasionally.........????? Yes, the bucket is used
heavily.
Any advice here?
-Chris
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