Messages in this thread | | | Date | Tue, 31 Aug 2010 12:55:23 +0300 | From | Boaz Harrosh <> | Subject | Re: [PATCH 26/30] ext4: do not send discards as barriers |
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On 08/31/2010 12:02 AM, Jan Kara wrote: > On Tue 31-08-10 00:39:41, Vladislav Bolkhovitin wrote: >> Jan Kara, on 08/31/2010 12:20 AM wrote: >>> On Mon 30-08-10 15:56:43, Jeff Moyer wrote: >>>> Jan Kara<jack@suse.cz> writes: >>>> >>>>> An update: I've set up an ext4 barrier testing in KVM - run fsstress, >>>>> kill KVM at some random moment and check that the filesystem is consistent >>>>> (kvm is run in cache=writeback mode to simulate disk cache). About 70 runs >>>> >>>> But doesn't your "disk cache" survive the "power cycle" of your guest? >>> Yes, you're right. Thinking about it now the test setup was wrong because >>> it didn't refuse writes to the VM's data partition after the moment I >>> killed KVM. Thanks for catching this. I will probably have to use the fault >>> injection on the host to disallow writing the device at a certain moment. >>> Or does somebody have a better option? >> >> Have you considered to setup a second box as an iSCSI target (e.g. >> with iSCSI-SCST)? With it killing the connectivity is just a matter >> of a single iptables command + a lot more options.
Still same problem no? the data is still cached on the backing store device how do you trash the cached data?
> Hmm, this might be an interesting option. Will try that. Thanks for > suggestion. > > Honza
with stgt it's very simple as well. It's a user mode application. All on the same machine: - run stgt application - login + mount a filesystem - run test - kill -9 stgt mid flight
But how to throw away the data on the backing store cache?
Boaz
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