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Hello everybody |
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|
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After 3 days messing around I'm at my wits' end. I have two Sun X4200M2 |
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servers which I would like to setup as Xen dom0s with a drbd-mirrored |
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file system for paravirtualized domU images. |
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|
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I setup an LVM2 on top of DRBD to create the domU volumes and to be able |
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to backup the domUs with LVM snapshot. |
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|
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I was able to configure this setup and make it run, but when accessing |
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the block-frontend device in domU this is terrible slow. E.g. copying a |
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5G file via scp and gigabit Ethernet onto the domU leads to a lot of |
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stalls during transfer. The peak transfer rate is about 5MB/s every 1-2 |
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minutes but generally it's about a few hundred KB/s. When copying the |
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same file onto the DRBD volume mounted directly in dom0 it works with |
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the expected 30-40MB/s. Another test was to sync the portage tree but |
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also this takes maybe about 20 minutes or spontaneously raises some |
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timeout errors. Sometimes after a while the disk fully detaches from the |
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domU, so every call of a binary in domU leads to a "Input/output error". |
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I guess the domU kernel adds this troubles, but why? There are no |
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statements in any log files. E.g. /var/log/xen/xend-debug.log doesn't |
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notify the detached block device. |
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|
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I use Gentoo Linux and tried so far with xen-3.1.2 and xen-3.2.0, |
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xen-sources-2.6.18-r8, xen-sources-2.6.20-r6 and xen-sources-2.6.22, |
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drbd-8.0.7, drbd-8.0.8 and drbd-8.0.11. |
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|
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The longer the more I expect a general problem with Xen and this setup, |
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a kernel problem or a misconfiguration. Attached are the most important |
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configurations for this setup. |
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|
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Are there any hints or other experiences for such a setup? All ideas are |
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welcome. |
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|
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Thanks for reading and giving any hints... |
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Cheers Reto Gantenbein |
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|
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|
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################ Configurations ################################# |
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|
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/etc/drbd.conf |
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,---------------------------------------------------------------- |
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| global { |
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| usage-count no; |
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| dialog-refresh 1; |
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| } |
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| |
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| common { |
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| startup { |
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| wfc-timeout 60; |
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| degr-wfc-timeout 60; |
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| } |
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| |
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| disk { |
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| on-io-error detach; |
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| # also tried 'pass-on' with same behavior |
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| } |
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| |
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| syncer { |
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| rate 500M; |
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| al-extents 80; |
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| } |
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| } |
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| |
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| resource "gentoo" { |
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| protocol C; |
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| net { |
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| # required for xen live migration |
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| allow-two-primaries; |
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| after-sb-0pri discard-zero-changes; |
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| after-sb-1pri discard-secondary; |
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| } |
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| |
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| on vserver03 { |
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| device /dev/drbd1; |
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| disk /dev/xen-vg/gentoo; |
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| address 10.0.0.1:7789; |
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| meta-disk internal; |
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| } |
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| |
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| on vserver04 { |
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| device /dev/drbd1; |
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| disk /dev/xen-vg/gentoo; |
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| address 10.0.0.2:7789; |
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| meta-disk internal; |
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| } |
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| } |
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`---------------------------------------------------------------- |
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|
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/etc/xen/gentoo |
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,---------------------------------------------------------------- |
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| name = "gentoo" |
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| |
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| kernel = "/cluster/xen/kernel/vmlinuz-gentoo-domU" |
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| extra = "" |
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| root = "/dev/hda1" |
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| |
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| memory = 4096 |
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| vcpus = 3 |
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| disk = [ 'drbd:gentoo,hda1,w' ] |
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| vif = [ 'mac=00:40:a6:00:45:01,bridge=xenbr-core', |
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| 'mac=00:40:a6:00:45:02,bridge=xenbr-public' ] |
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`---------------------------------------------------------------- |
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-- |
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