WARNING: libcurl doesn't support curl_multi_wait()
WARNING: cross zone / region transfer performance may be affected

If you have already been confronted to this error at startup of RadosGW, the problem is the version of libcurl used. To enable support of curl_multi_wait, you will need to compile radosgw with libcurl >= 7 …

A quick check of my Intel 520 SSD that running since 2 years on a small cluster.

smartctl -a /dev/sda
=== START OF INFORMATION SECTION ===
Model Family:     Intel 520 Series SSDs
Device Model:     INTEL SSDSC2CW060A3
Serial Number:    CVCV305200NB060AGN
LU WWN Device Id: 5 001517 8f36af9db
Firmware Version: 400i …

$ rados -p .default.rgw.buckets.index listomapkeys .dir.default.1970130.1 | wc -l
166768275

With each key containing between 100 and 250 bytes, this make a very big object for rados (several GB)... Especially when migrating it from an OSD to another (this will lock all writes), moreover, the OSD …

3.X Kernel for OpenVZ is out and it is compiled with rbd module:

root@debian:~# uname -a
Linux debian 3.10.0-3-pve #1 SMP Thu Jun 12 13:50:49 CEST 2014 x86_64 GNU/Linux

root@debian:~# modinfo rbd
filename:       /lib/modules/3.10.0-3-pve …

You have probably already be faced to migrate all objects from a pool to another, especially to change parameters that can not be modified on pool. For example, to migrate from a replicated pool to an EC pool, change EC profile, or to reduce the number of PGs... There are …