NexentaStor >> FreeNAS - RAM filling up, no Swap

[Nick Rozwadowski]

I finally gave up on NexentaStor and moved my pool to FreeNAS. I thought I would have to reformat and start my pool from scratch, but the OS was able to read my existing one; so I'm not starting from a "clean" setup right now.

I've got my shares setup and can access the pool via AFP and CIFS, but I'm having issues with my 8GB of RAM filling up which leads to crashes (nginx stalls, AFP/CIFS shares become unaccessible). I haven't had RAM problems in the past on this same system with NexentaStor. I'm not using deduplication.

1. I need help figuring out which processes could be bleeding the RAM

2. Can I setup swap after the fact, or do I need to start my pool from scratch?
--Can't find much info in the man pages

System Info:
-FreeNAS installed on a 4GB USB drive
-Intel Xeon X3430 on a Supermicro MB
-Mirrored 40GB SSDs as ZIL
-40GB SSD for L2ARC

top output, truncated (Swap is blank):

Code:

last pid:  4712;  load averages:  0.30,  0.36,  0.33    up 0+00:21:46  10:25:50
39 processes:  1 running, 38 sleeping
CPU:  0.0% user,  0.0% nice, 14.2% system,  1.1% interrupt, 84.7% idle
Mem: 176M Active, 109M Inact, 4118M Wired, 3664K Cache, 92M Buf, 3484M Free
ARC: 3400M Total, 83M MFU, 3236M MRU, 176K Anon, 71M Header, 9026K Other
Swap:
 
  PID USERNAME    THR PRI NICE  SIZE    RES STATE  C  TIME  WCPU COMMAND
3164 root          6  27    0  343M  128M usem    3  0:06  0.00% python2.7
3312 root          12  20    0  141M 11364K uwait  3  0:01  0.00% collectd
3310 root          2  52    0 85632K  8172K select  3  0:01  0.00% afpd
3872 root          1  52    0  158M 46404K ttyin  3  0:00  0.00% python2.7
3318 root          4  52    0  168M 46348K select  1  0:00  0.00% python2.7
...

 

[danb35]

8 GB is pretty minimal for FreeNAS--how large is your pool?

 

[gpsguy]

With just 8Gb RAM get rid of your L2ARC as a start.That's using your precious RAM. As danb35 said , we need more info about your system.


Sent from my phone

 

[Nick Rozwadowski]

8 GB is pretty minimal for FreeNAS--how large is your pool?

Code:

[root@freenas] ~# zpool list
NAME  SIZE  ALLOC  FREE    CAP  DEDUP  HEALTH  ALTROOT
pool  8.12T  6.57T  1.55T    80%  1.00x  ONLINE  /mnt

 

[Nick Rozwadowski]

With just 8Gb RAM get rid of your L2ARC as a start.That's using your precious RAM. As danb35 said , we need more info about your system.

Hmm, I'll look into that. Didn't realize that L2ARC eats system RAM; I'll check out the ZFS tuning guide for more info.

I don't mind buying more RAM to stabilize this system. My motherboard tops out at 32GB.

 

[Nick Rozwadowski]

With just 8Gb RAM get rid of your L2ARC as a start.That's using your precious RAM. As danb35 said , we need more info about your system.

FYI - here's a link to the formula for calculating L2ARC RAM requirements. I hadn't seen this before.

> Is there a guideline in which relation L2ARC size should be to RAM?
Approximately 200 bytes per record. I use the following example:
Suppose we use a Seagate LP 2 TByte disk for the L2ARC
+ Disk has 3,907,029,168 512 byte sectors, guaranteed
+ Workload uses 8 kByte fixed record size
RAM needed for arc_buf_hdr entries
+ Need = ~(3,907,029,168 - 9,232) * 200 / 16 = ~48 GBytes

Don't underestimate the RAM needed for large L2ARCs
-- richard

 

[Nick Rozwadowski]

Ordering 16GB of RAM. I'll reopen this if problems continue.