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Last modified by Drunk Monkey on 2024-09-01 09:09
From version 1.2
edited by Drunk Monkey
on 2024-09-01 09:06
Change comment: There is no comment for this version
To version 2.1
edited by Drunk Monkey
on 2024-09-01 09:09
Change comment: There is no comment for this version

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... ... @@ -13,7 +13,7 @@
13 13  Enter RAIDZ. Rather than the stripe width be statically set at creation, the stripe width is dynamic. Every block transactionally flushed to disk is its own stripe width. Every RAIDZ write is a full stripe write. Further, the parity bit is flushed with the stripe simultaneously, completely eliminating the RAID-5 write hole. So, in the event of a power failure, you either have the latest flush of data, or you don't. But, your disks will not be inconsistent.
14 14  
15 15  
16 -[[image:https://web.archive.org/web/20210430213528im_/https://pthree.org/wp-content/uploads/2012/12/raid5-vs-raidz11.png||alt="Image showing the stripe differences between RAID5 and RAIDZ-1."]]
16 +[[image:raid5-vs-raidz11.png]]
17 17  //Demonstrating the dynamic stripe size of RAIDZ//
18 18  
19 19  
... ... @@ -33,11 +33,12 @@
33 33  
34 34  To setup a zpool with RAIDZ-1, we use the "raidz1" VDEV, in this case using only 3 USB drives:
35 35  
36 -{{code language="bash session"}}# zpool create tank raidz1 sde sdf sdg
36 +{{code language="bash session"}}
37 +# zpool create tank raidz1 sde sdf sdg
37 37  # zpool status tank
38 38   pool: pool
39 39   state: ONLINE
40 - scan: none requested
41 + scan: none requested
41 41  config:
42 42  
43 43   NAME STATE READ WRITE CKSUM
... ... @@ -47,11 +47,14 @@
47 47   sdf ONLINE 0 0 0
48 48   sdg ONLINE 0 0 0
49 49  
50 -errors: No known data errors{{/code}}
51 +errors: No known data errors
52 +{{/code}}
51 51  
52 52  Cleanup before moving on, if following in your terminal:
53 53  
54 -{{code language="bash session"}}# zpool destroy tank{{/code}}
56 +{{code language="bash session"}}
57 +# zpool destroy tank
58 +{{/code}}
55 55  
56 56  === RAIDZ-2 ===
57 57  
... ... @@ -59,11 +59,12 @@
59 59  
60 60  To setup a zpool with RAIDZ-2, we use the "raidz2" VDEV:
61 61  
62 -{{code language="bash session"}}# zpool create tank raidz2 sde sdf sdg sdh
66 +{{code language="bash session"}}
67 +# zpool create tank raidz2 sde sdf sdg sdh
63 63  # zpool status tank
64 64   pool: pool
65 65   state: ONLINE
66 - scan: none requested
71 + scan: none requested
67 67  config:
68 68  
69 69   NAME STATE READ WRITE CKSUM
... ... @@ -74,11 +74,14 @@
74 74   sdg ONLINE 0 0 0
75 75   sdh ONLINE 0 0 0
76 76  
77 -errors: No known data errors{{/code}}
82 +errors: No known data errors
83 +{{/code}}
78 78  
79 79  Cleanup before moving on, if following in your terminal:
80 80  
81 -{{code language="bash session"}}# zpool destroy tank{{/code}}
87 +{{code language="bash session"}}
88 +# zpool destroy tank
89 +{{/code}}
82 82  
83 83  === RAIDZ-3 ===
84 84  
... ... @@ -86,7 +86,8 @@
86 86  
87 87  To setup a zpool with RAIDZ-3, we use the "raidz3" VDEV:
88 88  
89 -{{code language="bash session"}}# zpool create tank raidz3 sde sdf sdg sdh sdi
97 +{{code language="bash session"}}
98 +# zpool create tank raidz3 sde sdf sdg sdh sdi
90 90  # zpool status tank
91 91   pool: pool
92 92   state: ONLINE
... ... @@ -102,11 +102,14 @@
102 102   sdh ONLINE 0 0 0
103 103   sdi ONLINE 0 0 0
104 104  
105 -errors: No known data errors{{/code}}
114 +errors: No known data errors
115 +{{/code}}
106 106  
107 107  Cleanup before moving on, if following in your terminal:
108 108  
109 -{{code language="bash session"}}# zpool destroy tank{{/code}}
119 +{{code language="bash session"}}
120 +# zpool destroy tank
121 +{{/code}}
110 110  
111 111  === Hybrid RAIDZ ===
112 112  
... ... @@ -116,7 +116,8 @@
116 116  
117 117  To setup a zpool with 4 RAIDZ-1 VDEVs, we use the "raidz1" VDEV 4 times in our command. Notice that I've added emphasis on when to type "raidz1" in the command for clarity:
118 118  
119 -{{code language="bash session"}}# zpool create tank raidz1 sde sdf sdg raidz1 sdh sdi sdj raidz1 sdk sdl sdm raidz1 sdn sdo sdp
131 +{{code language="bash session"}}
132 +# zpool create tank raidz1 sde sdf sdg raidz1 sdh sdi sdj raidz1 sdk sdl sdm raidz1 sdn sdo sdp
120 120  # zpool status tank
121 121   pool: pool
122 122   state: ONLINE
... ... @@ -142,13 +142,16 @@
142 142   sdo ONLINE 0 0 0
143 143   sdp ONLINE 0 0 0
144 144  
145 -errors: No known data errors{{/code}}
158 +errors: No known data errors
159 +{{/code}}
146 146  
147 147  Notice now that there are four RAIDZ-1 VDEVs. As mentioned in a previous post, ZFS stripes across VDEVs. So, this setup is essentially a RAIDZ-1+0. Each RAIDZ-1 VDEV will receive 1/4 of the data sent to the pool, then each striped piece will be further striped across the disks in each VDEV. Nested VDEVs can be a great way to keep performance alive and well, long after the pool has been massively fragmented.
148 148  
149 149  Cleanup before moving on, if following in your terminal:
150 150  
151 -{{code language="bash session"}}# zpool destroy tank{{/code}}
165 +{{code language="bash session"}}
166 +# zpool destroy tank
167 +{{/code}}
152 152  
153 153  === Some final thoughts on RAIDZ ===
154 154