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Support multi-attach #120

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Akrog opened this issue Jun 6, 2019 · 1 comment · Fixed by #162
Closed

Support multi-attach #120

Akrog opened this issue Jun 6, 2019 · 1 comment · Fixed by #162
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enhancement New feature or request
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Ember-CSI

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@Akrog
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Akrog commented Jun 6, 2019

We should support multi-attach for block volumes even if we cannot support it for mount volumes.
@Akrog Akrog added the enhancement New feature or request label Jun 6, 2019
@Akrog Akrog added this to To do in Ember-CSI via automation Jun 6, 2019
@Akrog Akrog mentioned this issue Jan 8, 2020
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Akrog commented Jan 8, 2020

Multi-attach mount volumes would be problematic even on the single writer multiple readers scenario.

There are filesystems (like NTFS, and Ext4) that would corrupt the volume when we mount them on multiple hosts, even if they are read only.

We'll still have issues when we use other filesystems that don't have that issue, because Linux clients cache blocks locally, and they do not invalidate that cache. So we could experience application crashes when accessing data structures that were partially cached while being changed on the original.

Ext4 replays the journal even on readonly mounts. So a readonly mount will still write to the underlying block device. It would be unsafe even if both the mounts were readonly. We could try attaching the volume as readonly (or setting it to RO with blockdev --setro) before mounting and see it if works for the all readers (and no writers) case.

Akrog added a commit to Akrog/ember-csi that referenced this issue Apr 7, 2020
@Akrog
Add multi-access block support
7c211cd 
With this patch we now support RWX and ROX modes for block volumes, and
we fail for mount volumes.

Fix embercsi#120
@Akrog Akrog mentioned this issue Apr 7, 2020
Merged
Akrog added a commit to Akrog/ember-csi that referenced this issue Apr 8, 2020
@Akrog
Add multi-access block support
a758a78 
With this patch we now support RWX and ROX modes for block volumes, and
we fail for mount volumes.

Fix embercsi#120
Akrog added a commit to Akrog/ember-csi that referenced this issue Apr 8, 2020
@Akrog
Add multi-access block support
6075698 
With this patch we now support RWX and ROX modes for block volumes, and
we fail for mount volumes.

Fix embercsi#120
Ember-CSI automation moved this from To do to Done Apr 13, 2020
trgill pushed a commit to trgill/ember-csi that referenced this issue Apr 21, 2020
@Akrog @trgill
Add multi-access block support
754dae2 
With this patch we now support RWX and ROX modes for block volumes, and
we fail for mount volumes.

Fix embercsi#120
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enhancement New feature or request
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Add RWX for block volumes Akrog/ember-csi
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