Hi James, after having some discussion with the kernel guys and after digging through the kernel code and sending a patch today ;-) It is quite easy todo this via the kernel using this one: https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/commit/?id=39c60a0948cc06139e2fbfe084f83cb7e7deae3b Just do: echo temporary write through > /sys/class/scsi_disk/<disk>/cache_type for this disk and the kernel internally does not do any FLUSH. Even tough the command seems to disable write back it does not. But it still needs a patch of myself from today: Signed-off-by: Stefan Priebe <s.priebe@xxxxxxxxxxxx> --- drivers/scsi/sd.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 734a29a..ccc6242 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -174,7 +174,7 @@ sd_store_cache_type(struct device *dev, struct device_attribute *attr, if (sdkp->cache_override) { sdkp->WCE = wce; sdkp->RCD = rcd; - return count; + goto out; } if (scsi_mode_sense(sdp, 0x08, 8, buffer, sizeof(buffer), SD_TIMEOUT, @@ -194,6 +194,7 @@ sd_store_cache_type(struct device *dev, struct device_attribute *attr, sd_print_sense_hdr(sdkp, &sshdr); return -EINVAL; } +out: revalidate_disk(sdkp->disk); return count; } -- 1.7.10.4 Stefan Am 25.11.2013 10:59, schrieb James Pearce: > Having a configurable would be ideal. User should be made beware of the > need for super-caps via documentation in that case. > > Quickly eye-balling the code... can this be patched via journaller.cc > for testing? > _______________________________________________ > ceph-users mailing list > ceph-users@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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