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Last modified by Drunk Monkey on 2024-09-01 09:09
From version 2.1
edited by Drunk Monkey
on 2024-09-01 09:09
Change comment: There is no comment for this version
To version 1.2
edited by Drunk Monkey
on 2024-09-01 09:06
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:raid5-vs-raidz11.png]]
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."]]
17 17  //Demonstrating the dynamic stripe size of RAIDZ//
18 18  
19 19  
... ... @@ -33,12 +33,11 @@
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"}}
37 -# zpool create tank raidz1 sde sdf sdg
36 +{{code language="bash session"}}# zpool create tank raidz1 sde sdf sdg
38 38  # zpool status tank
39 39   pool: pool
40 40   state: ONLINE
41 - scan: none requested
40 + scan: none requested
42 42  config:
43 43  
44 44   NAME STATE READ WRITE CKSUM
... ... @@ -48,14 +48,11 @@
48 48   sdf ONLINE 0 0 0
49 49   sdg ONLINE 0 0 0
50 50  
51 -errors: No known data errors
52 -{{/code}}
50 +errors: No known data errors{{/code}}
53 53  
54 54  Cleanup before moving on, if following in your terminal:
55 55  
56 -{{code language="bash session"}}
57 -# zpool destroy tank
58 -{{/code}}
54 +{{code language="bash session"}}# zpool destroy tank{{/code}}
59 59  
60 60  === RAIDZ-2 ===
61 61  
... ... @@ -63,12 +63,11 @@
63 63  
64 64  To setup a zpool with RAIDZ-2, we use the "raidz2" VDEV:
65 65  
66 -{{code language="bash session"}}
67 -# zpool create tank raidz2 sde sdf sdg sdh
62 +{{code language="bash session"}}# zpool create tank raidz2 sde sdf sdg sdh
68 68  # zpool status tank
69 69   pool: pool
70 70   state: ONLINE
71 - scan: none requested
66 + scan: none requested
72 72  config:
73 73  
74 74   NAME STATE READ WRITE CKSUM
... ... @@ -79,14 +79,11 @@
79 79   sdg ONLINE 0 0 0
80 80   sdh ONLINE 0 0 0
81 81  
82 -errors: No known data errors
83 -{{/code}}
77 +errors: No known data errors{{/code}}
84 84  
85 85  Cleanup before moving on, if following in your terminal:
86 86  
87 -{{code language="bash session"}}
88 -# zpool destroy tank
89 -{{/code}}
81 +{{code language="bash session"}}# zpool destroy tank{{/code}}
90 90  
91 91  === RAIDZ-3 ===
92 92  
... ... @@ -94,8 +94,7 @@
94 94  
95 95  To setup a zpool with RAIDZ-3, we use the "raidz3" VDEV:
96 96  
97 -{{code language="bash session"}}
98 -# zpool create tank raidz3 sde sdf sdg sdh sdi
89 +{{code language="bash session"}}# zpool create tank raidz3 sde sdf sdg sdh sdi
99 99  # zpool status tank
100 100   pool: pool
101 101   state: ONLINE
... ... @@ -111,14 +111,11 @@
111 111   sdh ONLINE 0 0 0
112 112   sdi ONLINE 0 0 0
113 113  
114 -errors: No known data errors
115 -{{/code}}
105 +errors: No known data errors{{/code}}
116 116  
117 117  Cleanup before moving on, if following in your terminal:
118 118  
119 -{{code language="bash session"}}
120 -# zpool destroy tank
121 -{{/code}}
109 +{{code language="bash session"}}# zpool destroy tank{{/code}}
122 122  
123 123  === Hybrid RAIDZ ===
124 124  
... ... @@ -128,8 +128,7 @@
128 128  
129 129  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:
130 130  
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
119 +{{code language="bash session"}}# zpool create tank raidz1 sde sdf sdg raidz1 sdh sdi sdj raidz1 sdk sdl sdm raidz1 sdn sdo sdp
133 133  # zpool status tank
134 134   pool: pool
135 135   state: ONLINE
... ... @@ -155,16 +155,13 @@
155 155   sdo ONLINE 0 0 0
156 156   sdp ONLINE 0 0 0
157 157  
158 -errors: No known data errors
159 -{{/code}}
145 +errors: No known data errors{{/code}}
160 160  
161 161  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.
162 162  
163 163  Cleanup before moving on, if following in your terminal:
164 164  
165 -{{code language="bash session"}}
166 -# zpool destroy tank
167 -{{/code}}
151 +{{code language="bash session"}}# zpool destroy tank{{/code}}
168 168  
169 169  === Some final thoughts on RAIDZ ===
170 170