Administrator’s Command Line Guide

Chapter 4. Monitoring Storage Cluster
Status Description
replicating Percentage of chunks which are being replicated. Write operations on such chunks
are frozen until replication ends.
offline Percentage of chunks all replicas of which are offline. Such chunks are completely
inaccessible for the cluster and cannot be replicated, read from or written to. All
requests to an offline chunk are frozen until a CS that stores that chunk’s replica
goes online.
Get offline chunk servers back online as fast as possible to avoid losing data.
void Percentage of chunks that have been allocated but never used yet. Such chunks
contain no data. It is normal to have some void chunks in the cluster.
pending Percentage of chunks that must be replicated immediately. For a write request
from client to a chunk to complete, the chunk must have at least the set minimum
amount of replicas. If it does not, the chunk is blocked and the write request can-
not be completed. As blocked chunks must be replicated as soon as possible, the
cluster places them in a special high-priority replication queue and reports them
as pending.
blocked Percentage of chunks which have fewer active replicas than the set minimum
amount. Write requests to a blocked chunk are frozen until it has at least the
set minimum amount of replicas. Read requests to blocked chunks are allowed,
however, as they still have some active replicas left. Blocked chunks have higher
replication priority than degraded chunks.
Having blocked chunks in the cluster increases the risk of losing data, so postpone
any maintenance on working cluster nodes and get offline chunk servers back on-
line as fast as possible.
degraded Percentage of chunks with the number of active replicas lower than normal but
equal to or higher than the set minimum. Such chunks can be read from and
written to. However, in the latter case a degraded chunk becomes urgent.
urgent Percentage of chunks which are degraded and have non-identical replicas. Repli-
cas of a degraded chunk may become non-identical if some of them are not ac-
cessible during a write operation. As a result, some replicas happen to have the
new data while some still have the old data. The latter are dropped by the cluster
as fast as possible. Urgent chunks do not affect information integrity as the actual
data is stored in at least the set minimum amount of replicas.
standby Percentage of chunks that have one or more replicas in the standby state. A replica
is marked standby if it has been inactive for no more than 5 minutes.
50