# Object Server Configuration

This document describes the configuration options available for the object server. Documentation for other swift configuration options can be found at Configuration Documentation.

An Example Object Server configuration can be found at etc/object-server.conf-sample in the source code repository.

The following configuration sections are available:

- [DEFAULT]

- [object-server]

- [object-replicator]

- [object-reconstructor]

- [object-updater]

- [object-auditor]

- [object-expirer]

## [DEFAULT]

Option | Default | Description
swift_dir | /etc/swift | Swift configuration directory
devices | /srv/node | Parent directory of where devices are mounted
mount_check | true | Whether or not check if the devices are mounted to prevent accidentally writing to the root device
bind_ip | 0.0.0.0 | IP Address for server to bind to
bind_port | 6200 | Port for server to bind to
keep_idle | 600 | Value to set for socket TCP_KEEPIDLE
bind_timeout | 30 | Seconds to attempt bind before giving up
backlog | 4096 | Maximum number of allowed pending connections

workers

auto

Override the number of pre-forked workers that will accept connections. If set it should be an integer, zero means no fork. If unset, it will try to default to the number of effective cpu cores and fallback to one. Increasing the number of workers helps slow filesystem operations in one request from negatively impacting other requests, but only the servers_per_port option provides complete I/O isolation with no measurable overhead.

servers_per_port

0

If each disk in each storage policy ring has unique port numbers for its “ip” value, you can use this setting to have each object-server worker only service requests for the single disk matching the port in the ring. The value of this setting determines how many worker processes run for each port (disk) in the ring. If you have 24 disks per server, and this setting is 4, then each storage node will have 1 + (24 * 4) = 97 total object-server processes running. This gives complete I/O isolation, drastically reducing the impact of slow disks on storage node performance. The object-replicator and object-reconstructor need to see this setting too, so it must be in the [DEFAULT] section. See Running object-servers Per Disk.

max_clients | 1024 | Maximum number of clients one worker can process simultaneously (it will actually accept(2) N + 1). Setting this to one (1) will only handle one request at a time, without accepting another request concurrently.
disable_fallocate | false | Disable “fast fail” fallocate checks if the underlying filesystem does not support it.
log_name | swift | Label used when logging
log_facility | LOG_LOCAL0 | Syslog log facility
log_level | INFO | Logging level
log_address | /dev/log | Logging directory
log_max_line_length | 0 | Caps the length of log lines to the value given; no limit if set to 0, the default.
log_custom_handlers | None | Comma-separated list of functions to call to setup custom log handlers.
log_udp_host |  | Override log_address
log_udp_port | 514 | UDP log port
log_statsd_host | None | Enables StatsD logging; IPv4/IPv6 address or a hostname. If a hostname resolves to an IPv4 and IPv6 address, the IPv4 address will be used.
log_statsd_port | 8125 |
log_statsd_default_sample_rate | 1.0 |
log_statsd_sample_rate_factor | 1.0 |
log_statsd_metric_prefix |  |
eventlet_debug | false | If true, turn on debug logging for eventlet
fallocate_reserve | 1% | You can set fallocate_reserve to the number of bytes or percentage of disk space you’d like fallocate to reserve, whether there is space for the given file size or not. Percentage will be used if the value ends with a ‘%’. This is useful for systems that behave badly when they completely run out of space; you can make the services pretend they’re out of space early.
conn_timeout | 0.5 | Time to wait while attempting to connect to another backend node.
node_timeout | 3 | Time to wait while sending each chunk of data to another backend node.
client_timeout | 60 | Time to wait while receiving each chunk of data from a client or another backend node
network_chunk_size | 65536 | Size of chunks to read/write over the network
disk_chunk_size | 65536 | Size of chunks to read/write to disk
container_update_timeout | 1 | Time to wait while sending a container update on object update.

reclaim_age

604800

Time elapsed in seconds before the tombstone file representing a deleted object can be reclaimed. This is the maximum window for your consistency engine. If a node that was disconnected from the cluster because of a fault is reintroduced into the cluster after this window without having its data purged it will result in dark data. This setting should be consistent across all object services.

commit_window | 60 | Non-durable data files may also get reclaimed if they are older than reclaim_age, but not if the time they were written to disk (i.e. mtime) is less than commit_window seconds ago. A commit_window greater than zero is strongly recommended to avoid unintended reclamation of data files that were about to become durable; commit_window should be much less than reclaim_age.
nice_priority | None | Scheduling priority of server processes. Niceness values range from -20 (most favorable to the process) to 19 (least favorable to the process). The default does not modify priority.
ionice_class | None | I/O scheduling class of server processes. I/O niceness class values are IOPRIO_CLASS_RT (realtime), IOPRIO_CLASS_BE (best-effort), and IOPRIO_CLASS_IDLE (idle). The default does not modify class and priority. Linux supports io scheduling priorities and classes since 2.6.13 with the CFQ io scheduler. Work only with ionice_priority.
ionice_priority | None | I/O scheduling priority of server processes. I/O niceness priority is a number which goes from 0 to 7. The higher the value, the lower the I/O priority of the process. Work only with ionice_class. Ignored if IOPRIO_CLASS_IDLE is set.

## [object-server]

Option | Default | Description
use |  | paste.deploy entry point for the object server. For most cases, this should be `egg:swift#object`.
set log_name | object-server | Label used when logging
set log_facility | LOG_LOCAL0 | Syslog log facility
set log_level | INFO | Logging level
set log_requests | True | Whether or not to log each request
set log_address | /dev/log | Logging directory
user | swift | User to run as
max_upload_time | 86400 | Maximum time allowed to upload an object
slow | 0 | If > 0, Minimum time in seconds for a PUT or DELETE request to complete. This is only useful to simulate slow devices during testing and development.
mb_per_sync | 512 | On PUT requests, sync file every n MB
keep_cache_size | 5242880 | Largest object size to keep in buffer cache
keep_cache_private | false | Allow non-public objects to stay in kernel’s buffer cache
keep_cache_slo_manifest | false | Allow SLO object’s manifest file to stay in kernel’s buffer cache if its size is under keep_cache_size. This config will only matter when ‘keep_cache_private’ is false.
allowed_headers | Content-Disposition, Content-Encoding, X-Delete-At, X-Object-Manifest, X-Static-Large-Object Cache-Control, Content-Language, Expires, X-Robots-Tag | Comma separated list of headers that can be set in metadata on an object. This list is in addition to X-Object-Meta-* headers and cannot include Content-Type, etag, Content-Length, or deleted

replication_server

Configure parameter for creating specific server. To handle all verbs, including replication verbs, do not specify “replication_server” (this is the default). To only handle replication, set to a True value (e.g. “True” or “1”). To handle only non-replication verbs, set to “False”. Unless you have a separate replication network, you should not specify any value for “replication_server”.

replication_concurrency | 4 | Set to restrict the number of concurrent incoming SSYNC requests; set to 0 for unlimited
replication_concurrency_per_device | 1 | Set to restrict the number of concurrent incoming SSYNC requests per device; set to 0 for unlimited requests per devices. This can help control I/O to each device. This does not override replication_concurrency described above, so you may need to adjust both parameters depending on your hardware or network capacity.
replication_lock_timeout | 15 | Number of seconds to wait for an existing replication device lock before giving up.
replication_failure_threshold | 100 | The number of subrequest failures before the replication_failure_ratio is checked
replication_failure_ratio | 1.0 | If the value of failures / successes of SSYNC subrequests exceeds this ratio, the overall SSYNC request will be aborted
splice | no | Use splice() for zero-copy object GETs. This requires Linux kernel version 3.0 or greater. If you set “splice = yes” but the kernel does not support it, error messages will appear in the object server logs at startup, but your object servers should continue to function.
nice_priority | None | Scheduling priority of server processes. Niceness values range from -20 (most favorable to the process) to 19 (least favorable to the process). The default does not modify priority.
ionice_class | None | I/O scheduling class of server processes. I/O niceness class values are IOPRIO_CLASS_RT (realtime), IOPRIO_CLASS_BE (best-effort), and IOPRIO_CLASS_IDLE (idle). The default does not modify class and priority. Linux supports io scheduling priorities and classes since 2.6.13 with the CFQ io scheduler. Work only with ionice_priority.
ionice_priority | None | I/O scheduling priority of server processes. I/O niceness priority is a number which goes from 0 to 7. The higher the value, the lower the I/O priority of the process. Work only with ionice_class. Ignored if IOPRIO_CLASS_IDLE is set.

eventlet_tpool_num_threads

auto

The number of threads in eventlet’s thread pool. Most IO will occur in the object server’s main thread, but certain “heavy” IO operations will occur in separate IO threads, managed by eventlet. The default value is auto, whose actual value is dependent on the servers_per_port value. If servers_per_port is zero then it uses eventlet’s default (currently 20 threads). If the servers_per_port is nonzero then it’ll only use 1 thread per process. This value can be overridden with an integer value.

## [object-replicator]

Option | Default | Description
log_name | object-replicator | Label used when logging
log_facility | LOG_LOCAL0 | Syslog log facility
log_level | INFO | Logging level
log_address | /dev/log | Logging directory
daemonize | yes | Whether or not to run replication as a daemon
interval | 30 | Time in seconds to wait between replication passes
concurrency | 1 | Number of replication jobs to run per worker process
replicator_workers | 0 | Number of worker processes to use. No matter how big this number is, at most one worker per disk will be used. The default value of 0 means no forking; all work is done in the main process.
sync_method | rsync | The sync method to use; default is rsync but you can use ssync to try the EXPERIMENTAL all-swift-code-no-rsync-callouts method. Once ssync is verified as or better than, rsync, we plan to deprecate rsync so we can move on with more features for replication.
rsync_timeout | 900 | Max duration of a partition rsync
rsync_bwlimit | 0 | Bandwidth limit for rsync in kB/s. 0 means unlimited.
rsync_io_timeout | 30 | Timeout value sent to rsync –timeout and –contimeout options
rsync_compress | no | Allow rsync to compress data which is transmitted to destination node during sync. However, this is applicable only when destination node is in a different region than the local one. NOTE: Objects that are already compressed (for example: .tar.gz, .mp3) might slow down the syncing process.
stats_interval | 300 | Interval in seconds between logging replication statistics
handoffs_first | false | If set to True, partitions that are not supposed to be on the node will be replicated first. The default setting should not be changed, except for extreme situations.
handoff_delete | auto | By default handoff partitions will be removed when it has successfully replicated to all the canonical nodes. If set to an integer n, it will remove the partition if it is successfully replicated to n nodes. The default setting should not be changed, except for extreme situations.
node_timeout | DEFAULT or 10 | Request timeout to external services. This uses what’s set here, or what’s set in the DEFAULT section, or 10 (though other sections use 3 as the final default).
http_timeout | 60 | Max duration of an http request. This is for REPLICATE finalization calls and so should be longer than node_timeout.
lockup_timeout | 1800 | Attempts to kill all workers if nothing replicates for lockup_timeout seconds
rsync_module | {replication_ip}::object | Format of the rsync module where the replicator will send data. The configuration value can include some variables that will be extracted from the ring. Variables must follow the format {NAME} where NAME is one of: ip, port, replication_ip, replication_port, region, zone, device, meta. See etc/rsyncd.conf-sample for some examples.
rsync_error_log_line_length | 0 | Limits how long rsync error log lines are
ring_check_interval | 15 | Interval for checking new ring file
recon_cache_path | /var/cache/swift | Path to recon cache
nice_priority | None | Scheduling priority of server processes. Niceness values range from -20 (most favorable to the process) to 19 (least favorable to the process). The default does not modify priority.
ionice_class | None | I/O scheduling class of server processes. I/O niceness class values are IOPRIO_CLASS_RT (realtime), IOPRIO_CLASS_BE (best-effort), and IOPRIO_CLASS_IDLE (idle). The default does not modify class and priority. Linux supports io scheduling priorities and classes since 2.6.13 with the CFQ io scheduler. Work only with ionice_priority.
ionice_priority | None | I/O scheduling priority of server processes. I/O niceness priority is a number which goes from 0 to 7. The higher the value, the lower the I/O priority of the process. Work only with ionice_class. Ignored if IOPRIO_CLASS_IDLE is set.

## [object-reconstructor]

Option | Default | Description
log_name | object-reconstructor | Label used when logging
log_facility | LOG_LOCAL0 | Syslog log facility
log_level | INFO | Logging level
log_address | /dev/log | Logging directory
daemonize | yes | Whether or not to run reconstruction as a daemon
interval | 30 | Time in seconds to wait between reconstruction passes
reconstructor_workers | 0 | Maximum number of worker processes to spawn. Each worker will handle a subset of devices. Devices will be assigned evenly among the workers so that workers cycle at similar intervals (which can lead to fewer workers than requested). You can not have more workers than devices. If you have no devices only a single worker is spawned.
concurrency | 1 | Number of reconstruction threads to spawn per reconstructor process.
stats_interval | 300 | Interval in seconds between logging reconstruction statistics

handoffs_only

false

The handoffs_only mode option is for special case emergency situations during rebalance such as disk full in the cluster. This option SHOULD NOT BE CHANGED, except for extreme situations. When handoffs_only mode is enabled the reconstructor will only revert fragments from handoff nodes to primary nodes and will not sync primary nodes with neighboring primary nodes. This will force the reconstructor to sync and delete handoffs’ fragments more quickly and minimize the time of the rebalance by limiting the number of rebuilds. The handoffs_only option is only for temporary use and should be disabled as soon as the emergency situation has been resolved.

rebuild_handoff_node_count

2

The default strategy for unmounted drives will stage rebuilt data on a handoff node until updated rings are deployed. Because fragments are rebuilt on offset handoffs based on fragment index and the proxy limits how deep it will search for EC frags we restrict how many nodes we’ll try. Setting to 0 will disable rebuilds to handoffs and only rebuild fragments for unmounted devices to mounted primaries after a ring change. Setting to -1 means “no limit”.

max_objects_per_revert

0

By default the reconstructor attempts to revert all objects from handoff partitions in a single batch using a single SSYNC request. In exceptional circumstances max_objects_per_revert can be used to temporarily limit the number of objects reverted by each reconstructor revert type job. If more than max_objects_per_revert are available in a sender’s handoff partition, the remaining objects will remain in the handoff partition and will not be reverted until the next time the reconstructor visits that handoff partition i.e. with this option set, a single cycle of the reconstructor may not completely revert all handoff partitions. The option has no effect on reconstructor sync type jobs between primary partitions. A value of 0 (the default) means there is no limit.

node_timeout | DEFAULT or 10 | Request timeout to external services. The value used is the value set in this section, or the value set in the DEFAULT section, or 10.
http_timeout | 60 | Max duration of an http request. This is for REPLICATE finalization calls and so should be longer than node_timeout.
lockup_timeout | 1800 | Attempts to kill all threads if no fragment has been reconstructed for lockup_timeout seconds.
ring_check_interval | 15 | Interval for checking new ring file
recon_cache_path | /var/cache/swift | Path to recon cache
nice_priority | None | Scheduling priority of server processes. Niceness values range from -20 (most favorable to the process) to 19 (least favorable to the process). The default does not modify priority.
ionice_class | None | I/O scheduling class of server processes. I/O niceness class values are IOPRIO_CLASS_RT (realtime), IOPRIO_CLASS_BE (best-effort), and IOPRIO_CLASS_IDLE (idle). The default does not modify class and priority. Linux supports io scheduling priorities and classes since 2.6.13 with the CFQ io scheduler. Work only with ionice_priority.
ionice_priority | None | I/O scheduling priority of server processes. I/O niceness priority is a number which goes from 0 to 7. The higher the value, the lower the I/O priority of the process. Work only with ionice_class. Ignored if IOPRIO_CLASS_IDLE is set.
quarantine_threshold | 0 | The reconstructor may quarantine stale isolated fragments when it fails to fetch more than the quarantine_threshold number of fragments (including the stale fragment) during an attempt to reconstruct.
quarantine_age | reclaim_age | Fragments are not quarantined until they are older than quarantine_age, which defaults to the value of reclaim_age.

## [object-updater]

Option | Default | Description
log_name | object-updater | Label used when logging
log_facility | LOG_LOCAL0 | Syslog log facility
log_level | INFO | Logging level
log_address | /dev/log | Logging directory
interval | 300 | Minimum time for a pass to take
updater_workers | 1 | Number of worker processes
concurrency | 8 | Number of updates to run concurrently in each worker process
node_timeout | DEFAULT or 10 | Request timeout to external services. This uses what’s set here, or what’s set in the DEFAULT section, or 10 (though other sections use 3 as the final default).
objects_per_second | 50 | Maximum objects updated per second. Should be tuned according to individual system specs. 0 is unlimited.
slowdown | 0.01 | Time in seconds to wait between objects. Deprecated in favor of objects_per_second.
report_interval | 300 | Interval in seconds between logging statistics about the current update pass.
recon_cache_path | /var/cache/swift | Path to recon cache
nice_priority | None | Scheduling priority of server processes. Niceness values range from -20 (most favorable to the process) to 19 (least favorable to the process). The default does not modify priority.
ionice_class | None | I/O scheduling class of server processes. I/O niceness class values are IOPRIO_CLASS_RT (realtime), IOPRIO_CLASS_BE (best-effort), and IOPRIO_CLASS_IDLE (idle). The default does not modify class and priority. Linux supports io scheduling priorities and classes since 2.6.13 with the CFQ io scheduler. Work only with ionice_priority.
ionice_priority | None | I/O scheduling priority of server processes. I/O niceness priority is a number which goes from 0 to 7. The higher the value, the lower the I/O priority of the process. Work only with ionice_class. Ignored if IOPRIO_CLASS_IDLE is set.

## [object-auditor]

Option | Default | Description
log_name | object-auditor | Label used when logging
log_facility | LOG_LOCAL0 | Syslog log facility
log_level | INFO | Logging level
log_address | /dev/log | Logging directory
log_time | 3600 | Frequency of status logs in seconds.
interval | 30 | Time in seconds to wait between auditor passes
disk_chunk_size | 65536 | Size of chunks read during auditing
files_per_second | 20 | Maximum files audited per second per auditor process. Should be tuned according to individual system specs. 0 is unlimited.
bytes_per_second | 10000000 | Maximum bytes audited per second per auditor process. Should be tuned according to individual system specs. 0 is unlimited.
concurrency | 1 | The number of parallel processes to use for checksum auditing.
zero_byte_files_per_second | 50 |
object_size_stats |  |
recon_cache_path | /var/cache/swift | Path to recon cache
rsync_tempfile_timeout | auto | Time elapsed in seconds before rsync tempfiles will be unlinked. Config value of “auto” try to use object-replicator’s rsync_timeout + 900 or fallback to 86400 (1 day).
nice_priority | None | Scheduling priority of server processes. Niceness values range from -20 (most favorable to the process) to 19 (least favorable to the process). The default does not modify priority.
ionice_class | None | I/O scheduling class of server processes. I/O niceness class values are IOPRIO_CLASS_RT (realtime), IOPRIO_CLASS_BE (best-effort), and IOPRIO_CLASS_IDLE (idle). The default does not modify class and priority. Linux supports io scheduling priorities and classes since 2.6.13 with the CFQ io scheduler. Work only with ionice_priority.
ionice_priority | None | I/O scheduling priority of server processes. I/O niceness priority is a number which goes from 0 to 7. The higher the value, the lower the I/O priority of the process. Work only with ionice_class. Ignored if IOPRIO_CLASS_IDLE is set.

## [object-expirer]

Option | Default | Description
log_name | object-expirer | Label used when logging
log_facility | LOG_LOCAL0 | Syslog log facility
log_level | INFO | Logging level
log_address | /dev/log | Logging directory
interval | 300 | Time in seconds to wait between expirer passes
report_interval | 300 | Frequency of status logs in seconds.
concurrency | 1 | Level of concurrency to use to do the work, this value must be set to at least 1
dequeue_from_legacy | False | This service will look for jobs on the legacy expirer task queue.
round_robin_task_cache_size | 100000 | Number of tasks objects to cache before processing.
processes | 0 | How many parts to divide the legacy work into, one part per process that will be doing the work. When set 0 means that a single legacy process will be doing all the work. This can only be used in conjunction with `dequeue_from_legacy`.
process | 0 | Which of the parts a particular legacy process will work on. It is “zero based”, if you want to use 3 processes, you should run processes with process set to 0, 1, and 2. This can only be used in conjunction with `dequeue_from_legacy`.
reclaim_age | 604800 | How long an un-processable expired object marker will be retried before it is abandoned. It is not coupled with the tombstone reclaim age in the consistency engine.
request_tries | 3 | The number of times the expirer’s internal client will attempt any given request in the event of failure
recon_cache_path | /var/cache/swift | Path to recon cache
nice_priority | None | Scheduling priority of server processes. Niceness values range from -20 (most favorable to the process) to 19 (least favorable to the process). The default does not modify priority.
ionice_class | None | I/O scheduling class of server processes. I/O niceness class values are IOPRIO_CLASS_RT (realtime), IOPRIO_CLASS_BE (best-effort), and IOPRIO_CLASS_IDLE (idle). The default does not modify class and priority. Linux supports io scheduling priorities and classes since 2.6.13 with the CFQ io scheduler. Work only with ionice_priority.
ionice_priority | None | I/O scheduling priority of server processes. I/O niceness priority is a number which goes from 0 to 7. The higher the value, the lower the I/O priority of the process. Work only with ionice_class. Ignored if IOPRIO_CLASS_IDLE is set.
delay_reaping_<ACCT> | 0.0 | A dynamic configuration option for setting account level delay_reaping values. The delay_reaping value is configured for the account with the name placed in <ACCT>. The object expirer will reap objects in this account from disk only after this delay following their x-delete-at time.
delay_reaping_<ACCT>/<CNTR> | 0.0 | A dynamic configuration option for setting container level delay_reaping values. The delay_reaping value is configured for the container with the account name placed in <ACCT> and the container name in <CNTR>. The object expirer will reap objects in this container from disk only after this delay following their x-delete-at time.

this page last updated: 2026-04-08 16:47:21

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