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Amin's questions

Martin Hope
Amin
Asked: 2020-05-02 02:18:06 +0800 CST
  • 1

On a CentOS 7 server with 4X Samsung 800 SD with hard raid 10 I am using KVM for virtualization. I created a thin LVM storage for VMs and using "lvcreate -l 100%FREE --type thin-pool --thinpool thin_pool vgssd" gave me the following:

Thin pool volume with chunk size 1.00 MiB can address at most 253.00 TiB of data
WARNING: Pool zeroing and 1.00 MiB large chunk size slows down thin provisioning
WARNING: Consider disabling zeroing (-Zn) or using smaller chunk size (<512.00 KiB).
Logical volume "thin_pool" created.

What do you think about the chunk size? Is Zeroing necessary? VM performance is important to me, they are mostly Windows.

lvm windows-7 thin
Martin Hope
Amin
Asked: 2019-04-30 02:31:42 +0800 CST
  • -1

One of our servers faced random time restarts, we asked the dc to run hardware test and they said one of the SSD are likely failed. Could it be the reason for restarts in random times?

We have completed testing of the system and we are showing that SDD is showing signs of failure as shown by the following:

Device Model: Samsung SSD 840 EVO 500GB Serial Number:
S1DHNSAF218733W ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE 5 Reallocated_Sector_Ct 0x0033 098 098 010 Pre-fail Always
- 135 9 Power_On_Hours 0x0032 087 087 000 Old_age Always - 62573 12 Power_Cycle_Count 0x0032 099 099 000 Old_age Always - 109 177 Wear_Leveling_Count 0x0013 001 001 000 Pre-fail Always
- 1806 179 Used_Rsvd_Blk_Cnt_Tot 0x0013 098 098 010 Pre-fail Always - 135 181 Program_Fail_Cnt_Total 0x0032 100 100 010 Old_age Always - 0 182 Erase_Fail_Count_Total 0x0032 100 100 010 Old_age Always
- 0 183 Runtime_Bad_Block 0x0013 098 098 010 Pre-fail Always - 135 187 Reported_Uncorrect 0x0032 100 100 000 Old_age Always - 0 190 Airflow_Temperature_Cel 0x0032 065 052 000 Old_age Always
- 35 195 Hardware_ECC_Recovered 0x001a 200 200 000 Old_age Always - 0 199 UDMA_CRC_Error_Count 0x003e
100 100 000 Old_age Always - 0 235 Unknown_Attribute 0x0012 099 099 000 Old_age Always
- 107 241 Total_LBAs_Written 0x0032 099 099 000 Old_age Always - 269296231666

This is most likely what is causing the reboots of the system.

ssd
Martin Hope
Amin
Asked: 2017-03-14 01:43:54 +0800 CST
  • 6

To hide my website IP I proxied the main server with nginx on another VPS. I am trying to send the visitor real IP to my website and here is my config in conf.d folder:

proxy_cache_path  /etc/nginx/cacheddata  levels=1:2   keys_zone=staticfilecache:180m  max_size=500m;
proxy_temp_path /etc/nginx/cacheddata/temp;
proxy_connect_timeout 30;
proxy_read_timeout 120;
proxy_send_timeout 120;

#IMPORTANT - this sets the basic cache key that's used in the static file cache.
proxy_cache_key "$scheme://$host$request_uri";

upstream wordpressapache {
        #The upstream apache server. You can have many of these and weight them accordingly,
        #allowing nginx to function as a caching load balancer 
        server 127.0.0.1:8080 weight=1 fail_timeout=120s;
}
server {
      listen 80;
      server_name XXXXXX.com;
      access_log off;
      error_log off;
    set_real_ip_from 0.0.0.0/0;
    real_ip_header X-Real-IP;
    real_ip_recursive on;

# gzip compression options
  gzip on;
  gzip_http_version 1.0;
  gzip_comp_level 6;
  gzip_min_length 0;
  gzip_buffers 16 8k;
  gzip_proxied any;
  gzip_types text/plain text/css text/xml text/javascript application/xml application/xml+rss application/javascript application/json;
  gzip_disable "MSIE [1-6]\.";
  gzip_vary on;


      location / {
      proxy_pass http://XXXXXX/;
      proxy_redirect off;
      proxy_set_header Host $host;
      proxy_set_header X-Real-IP $remote_addr;
      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
      proxy_pass_request_headers on;
      proxy_max_temp_file_size 0;
      client_max_body_size 10m;
      client_body_buffer_size 128k;
      proxy_connect_timeout 90;
      proxy_send_timeout 90;
      proxy_read_timeout 90;
      proxy_buffer_size 4k;
      proxy_buffers 4 32k;
      proxy_busy_buffers_size 64k;
      proxy_temp_file_write_size 64k;
   }
}

And created a simple php page with this code on the proxied server:

<? echo $_SERVER["REMOTE_ADDR"]; ?>

When I open the page it displays the nginx server IP instead of my IP. Did I do anything wrong?

nginx reverse-proxy x-forwarded-for
Martin Hope
Amin
Asked: 2017-02-21 06:28:34 +0800 CST
  • 0

I found that there are many zombie LV in my CentOS 6 server which is being used for KVM vps hosting with LVM storage. Their attribute is "-wi-a-----" while normal LV attribute is "-wi-ao----". What I am doing now is exporting the lv list using "lvs" command and then filtering those LV with "-wi-a-----" attribute. Now I am looking for a command to remove these zombies in a faster way, like using lvremove -f xxxxxx.

lvm kvm-virtualization centos6