9b241e4a17
Currently, when removing shard special care must be taken with respect to shard numbering. `mode: disabled` allows to leave shard configuration in place while also ignoring it during initialization. This makes disk replacement much more convenient. Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
59 lines
1.5 KiB
Go
59 lines
1.5 KiB
Go
package mode
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import "math"
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// Mode represents enumeration of Shard work modes.
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type Mode uint32
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const (
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// ReadWrite is a Mode value for shard that is available
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// for read and write operations. Default shard mode.
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ReadWrite Mode = 0
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// DegradedReadOnly is a Mode value for shard that is set automatically
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// after a certain number of errors is encountered. It is the same as
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// `mode.Degraded` but also is read-only.
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DegradedReadOnly = Degraded | ReadOnly
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// Disabled mode is a mode where a shard is disabled.
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// An existing shard can't have this mode, but it can be used in
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// the configuration or control service commands.
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Disabled = math.MaxUint32
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)
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const (
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// ReadOnly is a Mode value for shard that does not
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// accept write operation but is readable.
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ReadOnly Mode = 1 << iota
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// Degraded is a Mode value for shard when the metabase is unavailable.
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// It is hard to perform some modifying operations in this mode, thus it can only be set by an administrator.
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Degraded
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)
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func (m Mode) String() string {
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switch m {
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default:
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return "UNDEFINED"
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case ReadWrite:
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return "READ_WRITE"
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case ReadOnly:
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return "READ_ONLY"
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case Degraded:
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return "DEGRADED_READ_WRITE"
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case DegradedReadOnly:
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return "DEGRADED_READ_ONLY"
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case Disabled:
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return "DISABLED"
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}
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}
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// NoMetabase returns true iff m is operating without the metabase.
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func (m Mode) NoMetabase() bool {
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return m&Degraded != 0
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}
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// ReadOnly returns true iff m prohibits modifying operations with shard.
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func (m Mode) ReadOnly() bool {
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return m&ReadOnly != 0
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}
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