Redis is configured to save RDB snapshots, but is currently not able to persist on disk - redis

I get the following error, whenever I execute any commands that modify data in redis
Redis is configured to save RDB snapshots, but is currently not able to persist on disk.
Commands that may modify the data set are disabled.
Please check Redis logs for details about the error.
I installed redis using brew on mac. How can I get the location of log files where redis-server logs information to. I tried looking for redis conf. file, but couldn't find it either.
What is the default location of [1] redis conf file [2] redis log file.
How do I get rid of the above error, and be able to execute commands that modify data in redis.

When installing with brew the logfile is set to stdout. You need to edit /usr/local/etc/redis.conf and change logfile to something else. I set mine to:
logfile /var/log/redis-server.log
You'll also make sure the user that runs redis has write permissions to the logfile, or redis will simply fail to launch completely. Then just restart redis:
brew services restart redis
After restarting it'll take a while for the error to show up in the logs, because it happens after redis fails its timed flushes. You should be seeing something like:
[7051] 29 Dec 02:37:47.164 # Background saving error
[7051] 29 Dec 02:37:53.009 * 10 changes in 300 seconds. Saving...
[7051] 29 Dec 02:37:53.010 * Background saving started by pid 7274
[7274] 29 Dec 02:37:53.010 # Failed opening .rdb for saving: Permission denied
After a brew install it attempts to save to /usr/local/var/db/redis/ and since redis is probably running as your current user and not root, it can't write to it. Once redis has permission to write to the directory, your logfile will say:
[7051] 29 Dec 03:08:59.098 * 1 changes in 900 seconds. Saving...
[7051] 29 Dec 03:08:59.098 * Background saving started by pid 8833
[8833] 29 Dec 03:08:59.099 * DB saved on disk
[7051] 29 Dec 03:08:59.200 * Background saving terminated with success
and the stop-writes-on-bgsave-error error will no longer get raised.

So I guess it is a bit late for adding an answer here but since I wondered on your question as I had the same error. I got it solved by changing my redis.conf 's dir variable like this:
# The filename where to dump the DB
dbfilename dump.rdb
# The working directory.
#
# The DB will be written inside this directory, with the filename specified
# above using the 'dbfilename' configuration directive.
#
# The Append Only File will also be created inside this directory.
#
# Note that you must specify a directory here, not a file name.
dir /root/path/to/dir/with/write/access/
The default value is: ./, so depending on how you launch your redis server you might not be able to save snapshots.
Hope it helps someone !

In my case i resolved this issue with below steps
Cause : By default redis store data # ./ and if redis runs with redis user this means redis will not be able to write data in ./ file then you will face above error.
Resolution :
Step # 1 (Enter a valid location where redis can do write operations)
root#fpe:/var/lib/redis# vim /etc/redis/redis.conf
dir /var/lib/redis # ( This location must have right for redis user to write)
Step # 2 (Connect to redis cli and map directory to write and issue below variable)
127.0.0.1:6379> CONFIG SET dir "/var/lib/redis"
127.0.0.1:6379> BGSAVE -
This will enable redis to write data on dump file.

Was going through the github discussion and the proposed solution is
to run
config set stop-writes-on-bgsave-error no
in the redis-cli.
here's the link
https://github.com/redis/redis/issues/584#issuecomment-11416418

Steps to fix this error:
Go to redis cli by typing redis-cli
127.0.0.1:6379> config set stop-writes-on-bgsave-error no
after that try to set key value
127.0.0.1:6379> set test_key 'Test Value'
127.0.0.1:6379> get test_key
"Test Value"

Check the following places:
/usr/local/Cellar/redis...
/usr/local/var/log/redis.log
/usr/local/etc/redis.conf
This error often indicates an issue with write permissions, make sure you're RDB directory is writable.

It is usually because permission limits. In my case, it's redis disabled write options.
You can try to run redis-cli in the shell, and then run the following command:
set stop-writes-on-bgsave-error yes

Related

redis snapshot location not as specified in config

After running fine for a while, I am getting write error on my redis instance:
(error) MISCONF Redis is configured to save RDB snapshots, but it is currently not able to persist on disk. Commands that may modify the data set are disabled, because this instance is configured to report errors during writes if RDB snapshotting fails (stop-writes-on-bgsave-error option). Please check the Redis logs for details about the RDB error.
In the log I see:
9948:C 22 Mar 20:49:32.241 # Failed opening the RDB file root (in server root dir /var/spool/cron) for saving: Read-only file system
However, my redis config file is /etc/redis/redis.conf as confirmed by:
redis-cli -p 6379 info | grep 'config_file'
config_file:/etc/redis/redis.conf
And there I have:
dir /mnt/data/redis
And indeed, there is a snapshot there.
But despite the above, redis now thinks my data directory is
redis-cli -p 6379 CONFIG GET dir
1) "dir"
2) "/var/spool/cron"
Corresponding to the error I was getting as quoted above.
Can anyone tell me why/how my data directory is changing after redis starts, such that it is no longer what is specified in the config file?
So the answer is that the redis server was hacked and the configuration changed, which is very easy to do as it turns out. (I should point out that I had no reason to think it wasn't easy to do. I just assumed security by obscurity was sufficient in this case--wrong. No matter, this was just a playground not any sort of production server).
So don't open your redis port to the world. Use security groups if on AWS to limit access to machines that need it, or use AUTH (which is still not awesome because then all clients need to know the single password which also apparently gets sent in the clear), or have some middleware controlling access.
Hacking redis is easy to do, can compromise your data, and even enable unauthorized SSH access to your server. And that's why you shouldn't highline.

How to start `redis-sentinel` server successfully

Sorry redis newbie here.
When I run redis-sentinel
42533:X 10 Nov 21:21:30.345 # Warning: no config file specified, using
the default config. In order to specify a config file use redis-
sentinel /path/to/sentinel.conf
42533:X 10 Nov 21:21:30.346 * Increased maximum number of open files to
10032 (it was originally set to 7168).
Redis 3.0.4 (00000000/0) 64 bit
Running in sentinel mode
Port: 26379
PID: 42533
http://redis.io
42533:X 10 Nov 21:21:30.347 # Sentinel runid is
733213860cf470431c7441e5d6aaf9ed9b2d7c2f
42533:X 10 Nov 21:21:30.347 # Sentinel started without a config file.
Exiting...
What am I missing? Do I need a configuration file? If so where should my /path/to/sentinel.conf be?
It is mandatory to use a configuration file when running Sentinel, as this file will be used by the system in order to save the current state that will be reloaded in case of restarts. Sentinel will simply refuse to start if no configuration file is given or if the configuration file path is not writable.
you can run Sentinel with the following command line:
redis-sentinel /path/to/sentinel.conf
Otherwise you can use directly the redis-server executable starting it in Sentinel mode:
redis-server /path/to/sentinel.conf --sentinel
You can put the file anywhere you want, just make sure you are providing the right path for that. For example, if you are in linux and if the file is inside your home directory, then the command will be
redis-sentinel ~/sentinel.conf

How to configure Redis to persist data after reboot on Linux?

I installed Redis on Ubuntu 16.04. I couldn't find Redis directory nor redis.conf file (tried with: sudo find redis.conf).
My application depends on some data pulled from third party APIs. I store the (processed) data in Redis. My problem is, after reboot I lose the data. I guess I need to specify in config file that the data should be persisted on reboot, but I couldn't find the config file. Do I need to create the config file? Are there some templates to use? My goal is just to have the data persisted after reboot.
Thank you!
Use dpkg -L redis-server | grep redis.conf to find config file path. It should be located at /etc/redis/redis.conf as I know.
Redis has 2 methods for persistense: Snapshotting and Append-only file:
Snapshotting will be enabled by adding (or uncommenting) save X Y in config file. It means Redis will automatically dump the dataset to disk every X seconds if at least Y keys changed. There could be more than one save options in config file.
Append-only file will be enabled by adding (or uncommenting) appendonly yes in config file
you should turn on the rdb or aof.
see https://redis.io/topics/persistence
Add this to the config file.
appendonly yes
This will append data as you store new data. This enables durability.

How to disable Redis RDB and AOF?

How to completely disable RDB and AOF?
I don't care about Persistence and want it to be in mem only.
I have already commented out the:
#save 900 1
#save 300 10
#save 60 10000
But this did not help and I see that Redis still tries to write to disk.
I know that Redis wants to write to disk because I get this error: "Failed opening .rdb for saving: Permission denied"
I don't care about the error, because I want to disable the Persistence altogether.
If you want to change the redis that is running, log into the redis, and
disable the aof:
config set appendonly no
disable the rdb:
config set save ""
If you want to make these changes effective after restarting redis, using
config rewrite
to make these changes to redis conf file.
If your redis have not started, just make some changes to redis.conf,
appendonly no
save ""
make sure there are no sentences like "save 60 1000" after the upper sentences, since the latter would rewrite the former.
Update: please look at Fibonacci's answer. Mine is wrong, although it was accepted.
Commenting the "dbfilename" line in redis.conf should do the trick.

Redis crashes instantly without error

I've got redis installed on my VM, and I haven't used it in a while. (Last I was using it, it did work, and now it doesn't.. nothing's changed in that time (about a month)). Needless to say I'm deeply confused but I'll post as much info as I can.
$ redis-server
Server starts, but throws a warning about overcommit memory being set to 0. I'm on a VM, so I can't change this setting from 0 to 1 if I wanted, which I wouldn't want to anyway for my purposes. I've written a custom redis.config file though, which I want it to use (and which I was using in the past), so starting it with the default config file doesn't do me much good. Let's try this again.
$ redis-server redis.config
$
Nothing. Silence. No error message, just didn't start.
$ nohup redis-server redis.config > nohup.out&
I get a process ID, but then $ ps and I see the the process is listed as stop and shortly disappears. Again, no errors, and no output in nohup.out nor in the log file for redis. Below is the redis.config I'm using (without the comments to keep it short)
daemonize yes
pidfile [my-user-account-path]/redis/redis.pid
port 0
bind 127.0.0.1
unixsocket [my-user-account-path]/tmp/redis.sock
unixsocketperm 770
timeout 10
tcp-keepalive 60
loglevel warning
logfile [my-user-account-path]/redis/logs/redis.log
databases 16
save 900 1
save 300 10
save 60 10000
stop-writes-on-bgsave-error no
rdbcompression no
rdbchecksum no
dbfilename dump.rdb
dir [my-user-account-path]/redis/db
slave-serve-stale-data yes
slave-priority 100
appendonly no
lua-time-limit 5000
slowlog-log-slower-than 10000
slowlog-max-len 128
# ADVANCED CONFIG is set to all default settings#
I'm sure it's probably something stupid, probably even a permissions thing somewhere (I've tried executing this as root, fyi), to no avail. Anyone ever experience something similar with Redis?
i have been experiencing redis crashes as well. just an fyi - the guy responsible for much of redis' development, Salvatore Sanfilippo, aka antirez, keeps an interesting blog that has some insight on redis crashes:
http://antirez.com/news/43