docs(failure-domains): name domains with labels instead of integer ids

.claude/skills/documentation-writing/SKILL.md

@@ -208,6 +208,13 @@ so write `NVMe devices`.
 `behavior`, `labeled`, `enroll`, `artifact`, `program`, `license`, `gray`. Note
 that `Fibre Channel` is the name of a standard and keeps its spelling.
 
+**A compound with two accepted spellings is written the house way.** `datacenter`
+is one word, never "data center" or "data-center". Neither spelling is wrong,
+which is exactly why one of them is picked: a page that alternates between them
+reads as two pages. The list is `ONE_WORD_COMPOUNDS` in
+`scripts/check-prose.py`, and a new pair is added there rather than settled per
+page.
+
 **The Oxford comma** goes before the final `and`, `or`, or `nor` of a series of
 three or more items: "storage nodes, volumes, and snapshots". It belongs to a
 series and nowhere else. A comma before an `and` that joins two sentences is
@@ -216,16 +223,30 @@ nothing to insert.
 
 ## Punctuation to avoid
 
-Three habits make a page read as though nobody chose the words. The punctuation
-gate reports all of them. The first two are warnings, because what replaces them
-depends on the sentence and is a decision for the writer. The list item form and
-the placement of a mark have one right answer and are errors that `--fix`
+A handful of habits make a page read as though nobody chose the words, and the
+gates report all of them. The semicolon and the em dash below are warnings,
+because what replaces them depends on the sentence and is a decision for the
+writer. Everything else has one right answer and is an error that `--fix`
 resolves.
 
 **A missing comma after an abbreviation.** American usage writes "e.g.," and
 "i.e.," and "for example," with the comma, since each of them introduces the
 example that follows.
 
+**A missing comma after an opening connective or sentence adverb.** "However,",
+"Therefore,", "Otherwise,", "Internally,", "By default,", "Today,". The comma is
+what marks the word as a comment on the whole sentence rather than as part of
+it, and without it the reader parses the word as the subject and has to start
+over. The full list is in `scripts/check-prose.py`.
+
+The comma belongs to the word only where the word opens a clause. "Instead of",
+"Now that", "Together with" and "In addition to" are prepositions and
+conjunctions that carry the comma behind the whole phrase, and "Initially
+developed by Google" is an adverb modifying a participle. The check knows all
+three shapes and leaves them alone. "Then" and "First" are absent from it
+entirely, because they number the steps of a procedure: "Then apply the change"
+takes no comma.
+
 **A comma and a full stop go inside the closing quotation mark**, whatever the
 quoted words are: "docking points," and never "docking points",. A colon and a
 semicolon stay outside, and a question mark belongs to whichever sentence asks

docs/architecture/concepts/failure-domains.md

@@ -9,9 +9,14 @@ distribution unit, or an availability zone. When failure domains are enabled, si
 journal copies, and failover paths across the domains so that the loss of one entire domain does not interrupt
 the availability of the cluster.
 
-Failure domains are identified by a non-negative integer chosen by the operator. Simplyblock does not detect the
-physical topology itself: every storage node is explicitly tagged with the id of the domain it belongs to when it
-is added to the cluster.
+Each domain is identified by a label, such as `RACK1`, `AZ2`, or `HOST1`. Simplyblock does not detect the
+physical topology itself: every storage node is explicitly tagged with the label of the domain it belongs to when
+it is added to the cluster. The domain is created by the first node carrying a given label, and every later node
+naming that label joins it.
+
+Internally, each label maps to a cluster-unique integer id, which is what placement and the data plane key off.
+That id is assigned automatically and does not have to be tracked. It surfaces only in low-level logs and in the
+`failure_domain` field of the API, which keeps its integer type for compatibility.
 
 !!! important
     Failure-domain support is a deploy-time decision. It is enabled when the storage cluster is created and cannot
@@ -22,7 +27,7 @@ is added to the cluster.
 With failure domains enabled, placement decisions consider the domain tag in four independent dimensions:
 
 1. **Data and parity chunks:** The distributed erasure coding spreads the chunks of each stripe across distinct
-   failure domains, so that a full domain outage leaves enough chunks to reconstruct all data within the configured
+   failure domains so that a full domain outage leaves enough chunks to reconstruct all data within the configured
    erasure coding scheme.
 2. **Journal copies:** The copies of the high-availability write journal are balanced across domains with a
    per-domain cap, so that losing a whole domain always leaves enough journal copies to maintain the journal quorum.
@@ -66,7 +71,7 @@ a same-domain secondary path, and its tertiary path is still guaranteed to be cr
 
 !!! note
     Balance is counted in physical hosts, not storage nodes. On multi-socket hosts running two storage nodes, both
-    nodes count as one host and must carry the same failure-domain id. Dedicated secondary nodes are not counted
+    nodes count as one host and must carry the same failure-domain label. Dedicated secondary nodes are not counted
     toward the balance.
 
 ## Failure Domains and Erasure Coding Schemes
@@ -85,7 +90,7 @@ its loss would break the journal quorum.
 ## Domain Membership Is Immutable
 
 A host's failure domain cannot be changed while the host is part of the cluster. Moving a host between domains
-requires removing the node, restoring the domain balance, and re-adding it with the new failure-domain id. This
+requires removing the node, restoring the domain balance, and re-adding it with the new failure-domain label. This
 prevents accidental topology changes that would silently invalidate the placement of existing data.
 
 ## Recovery Behavior

docs/architecture/concepts/hyper-converged.md

@@ -31,7 +31,7 @@ Key characteristics and benefits of hyper-converged storage include:
   New nodes can be added seamlessly, increasing both compute and storage capacity without complex
   reconfiguration. Storage capacity and performance grows and shrinks seamlessly with the size of the cluster.
   This provides a great deal of flexibility for customers with strong and unknown dynamics as well as those with a variety of different sizing
-  requirements from small edge clusters to large data center clusters.
+  requirements from small edge clusters to large datacenter clusters.
 -  **De-coupling from Hardware Lifecycle** Individual hardware components or units can be replaced choosing from different vendors
 without service interruption or degradation. Gradual replacement of hardware is supported.
 

docs/architecture/concepts/nvme-namespaces-and-subsystems.md

@@ -22,7 +22,7 @@ In simplyblock this process is either automated (CSI, OpenStack, or Proxmox) or
 
 It’s roughly equivalent to an NVMe controller or logical device that can contain one or more namespaces.
 
-Now subsystems are backed by multiple queue pairs, each of which is backed by a network connection such as a TCP socket.
+Now, subsystems are backed by multiple queue pairs, each of which is backed by a network connection such as a TCP socket.
 More queue pairs require more resources from the cluster but make the volumes faster.
 
 Namespaces on the other side are actual block storage regions that hold user data.

docs/architecture/storage-performance-and-qos.md

@@ -90,7 +90,7 @@ bottlenecks specific to mixed I/O patterns on other protocols (such as iSCSI) an
 ### Support for ROCEv2
 
 Simplyblock also supports NVMe over RDMA (ROCEv2). RDMA, as a transport layer, offers significant latency and tail
-latency advantages over TCP. Today, RDMA can be used in most data center environments because it requires only specific
+latency advantages over TCP. Today, RDMA can be used in most datacenter environments because it requires only specific
 hardware features from NICs, which are available across a broad range of models. It runs over UDP/IP and, as such, does
 not require any changes to the networking.
 

docs/deployment-preparation/cloud-instance-recommendations.md

@@ -14,7 +14,7 @@ Amazon EBS is not recommended for high-performance clusters.
 
 !!! important
     If local NVMe devices are chosen, make sure that the nodes in the cluster are provisioned into a placement group of type
-    _Spread_! Otherwise there is no guarantee that multiple storage nodes won't be located in the same failure domain.
+    _Spread_! Otherwise, there is no guarantee that multiple storage nodes won't be located in the same failure domain.
 
 Generally, with AWS, there are three considerations when selecting virtual machine types:
 

docs/important-notes/terminology.md

@@ -18,7 +18,7 @@ fault-tolerant, and high-performance storage system. Unlike traditional single-n
 distribute data across multiple nodes, ensuring redundancy, load balancing, and resilience against hardware failures. To
 optimize data availability and efficiency, these clusters can be configured using different architectures, including
 replication and erasure coding. Storage clusters are commonly used in cloud storage, high-performance computing (HPC),
-and enterprise data centers, enabling seamless scalability and improved data accessibility across distributed
+and enterprise datacenters, enabling seamless scalability and improved data accessibility across distributed
 environments.
 
 ### Storage Node
@@ -67,7 +67,7 @@ infrastructures, providing fast and efficient remote storage access.
 NVMe/TCP (NVMe over TCP) is a transport protocol that extends NVMe over Fabrics (NVMe-oF) using standard TCP/IP networks
 to enable high-performance, low-latency access to remote NVMe storage. By leveraging existing Ethernet infrastructure,
 NVMe/TCP eliminates the need for specialized networking hardware such as RDMA (RoCE or iWARP) or Fibre Channel (FC),
-making it a cost-effective and easily deployable solution for cloud, enterprise, and data center storage environments.
+making it a cost-effective and easily deployable solution for cloud, enterprise, and datacenter storage environments.
 It maintains the efficiency of NVMe, providing scalable, high-throughput, and low-latency remote storage access while
 ensuring broad compatibility with modern network architectures.
 
@@ -309,7 +309,7 @@ software-defined system. Unlike traditional architectures that rely on separate
 hyper-converged infrastructure (HCI) leverages virtualization and centralized management to streamline operations,
 improve scalability, and reduce complexity. This approach enhances performance, fault tolerance, and resource efficiency
 by distributing workloads across multiple nodes, allowing seamless scaling by adding more nodes. HCI is widely
-used in cloud environments, virtual desktop infrastructure (VDI), and enterprise data centers for its ease of
+used in cloud environments, virtual desktop infrastructure (VDI), and enterprise datacenters for its ease of
 deployment, automation capabilities, and cost-effectiveness.
 
 ### Disaggregated
@@ -319,5 +319,5 @@ independent components rather than tightly integrated within the same physical s
 for example, storage resources are managed independently of compute nodes, allowing for flexible scaling, improved
 resource utilization, and reduced hardware dependencies. This contrasts with traditional or hyper-converged
 architectures, where these resources are combined. Disaggregated architectures are widely used in cloud computing,
-high-performance computing (HPC), and modern data centers to enhance scalability, cost-efficiency, and operational
+high-performance computing (HPC), and modern datacenters to enhance scalability, cost-efficiency, and operational
 flexibility while optimizing performance for dynamic workloads.

docs/kubernetes/usage/removing.md

@@ -31,7 +31,7 @@ When the PVC is deleted, the PersistentVolume state must be checked. It should b
 kubectl get pv
 ```
 
-Now the PV can be deleted:
+Now, the PV can be deleted:
 
 ```bash title="Delete a PersistentVolume"
 kubectl delete pv <pv-name>

docs/kubernetes/usage/snapshotting.md

@@ -9,7 +9,7 @@ simplyblock's [copy-on-write](../../important-notes/terminology.md#cow-copy-on-w
 
 In simplyblock, a snapshot is comparable to the table of contents in a book, meaning that the snapshot refers to the same
 data as the original volume. If the volume diverges from the snapshot, the mutated data segment is duplicated, changed,
-and stored as a new data block. Now the volume refers to the new block, while the snapshot refers to the old one.
+and stored as a new data block. Now, the volume refers to the new block, while the snapshot refers to the old one.
 
 A deeper explanation can be found here: