From 802ce7be9e82354437fcfa3c30085e812d5c878c Mon Sep 17 00:00:00 2001 From: Brian Behlendorf Date: Wed, 5 Feb 2020 10:41:16 -0800 Subject: [PATCH] Add sending large block section --- FAQ.md | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/FAQ.md b/FAQ.md index 116fa11..c7f2a32 100644 --- a/FAQ.md +++ b/FAQ.md @@ -12,7 +12,9 @@ - [Changing /dev/ names on an existing pool](#changing-dev-names-on-an-existing-pool) - [The /etc/zfs/zpool.cache file](#the-etczfszpoolcache-file) - [Generating a new /etc/zfs/zpool.cache file](#generating-a-new-etczfszpoolcache-file) -- [hole_birth Bugs](#hole_birth-bugs) +- [Sending and Receiving Streams](#sending-and-receiving-streams) + * [hole_birth Bugs](#hole_birth-bugs) + * [Sending Large Blocks](#sending-large-blocks) - [CEPH/ZFS](#cephzfs) * [ZFS Configuration](#zfs-configuration) * [CEPH Configuration (ceph.conf}](#ceph-configuration-cephconf) @@ -232,8 +234,9 @@ Conversely the cache file can be disabled by setting `cachefile=none`. This is ``` $ zpool set cachefile=none tank ``` +## Sending and Receiving Streams -## hole_birth Bugs +### hole_birth Bugs The hole_birth feature has/had bugs, the result of which is that, if you do a `zfs send -i` (or `-R`, since it uses `-i`) from an affected dataset, the receiver *will not see any checksum or other errors, but will not match the source*. @@ -241,6 +244,13 @@ ZoL versions 0.6.5.8 and 0.7.0-rc1 (and above) default to ignoring the faulty me For more details, see the [[hole_birth FAQ]]. +### Sending Large Blocks + +When sending incremental streams which contain large blocks (>128K) the `--large-block` flag must be specified. Inconsist use of the flag between incremental sends can result in files being incorrectly zeroed when they are received. Raw encrypted send/recvs automatically imply the `--large-block` flag and are therefore unaffected. + +For more details, see [issue 6224](https://github.com/zfsonlinux/zfs/issues/6224). + + ## CEPH/ZFS There is a lot of tuning that can be done that's dependent on the workload that is being put on CEPH/ZFS, as well as some general guidelines. Some are as follow;