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Bug #941

perhaps zfs vdev_cache logic should be removed.

Added by Garrett D'Amore over 8 years ago. Updated over 8 years ago.

Status:
New
Priority:
Low
Assignee:
-
Category:
zfs - Zettabyte File System
Start date:
2011-04-21
Due date:
% Done:

0%

Estimated time:
Difficulty:
Tags:

History

#1

Updated by Garrett D'Amore over 8 years ago

  • Category set to zfs - Zettabyte File System
  • Priority changed from Normal to Low

So the following change was added as part of bug 175 :

+
+ * TODO: Note that with the current ZFS code, it turns out that the
+ * vdev cache is not helpful, and in some cases actually harmful. It
+ * is better if we disable this. Once some time has passed, we should
+ * actually remove this to simplify the code. For now we just disable
+ * it by setting the zfs_vdev_cache_size to zero. Note that Solaris 11
+ * has made these same changes.
*/
int zfs_vdev_cache_max = 1<<14; /
16KB /
-int zfs_vdev_cache_size = 10ULL << 20; /
10MB */
+int zfs_vdev_cache_size = 0;
int zfs_vdev_cache_bshift = 16;

Given that this disables the vdev cache entirely, perhaps we should remove it. But not until some operational experience is gained to determine whether there are cases where the cache should be reenabled.

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