Invalid Page Header Error

Hello,

We had a server crash and when restarting postgres it works, except some
"Invalid Page Header Error" :

I already try VACUUM / FULL / ANALYSE but same error

Even when doing a pg_dumpall, we have this problem.

$ pg_dumpall >/dev/null
pg_dump: ERREUR:  en-tête de page invalide dans le bloc 6142 de la
relation « articles_hs »
pg_dump: La commande SQL de sauvegarde du contenu de la table «
articles_hs » a échoué : échec
de PQendcopy().
pg_dump: Message d'erreur du serveur : ERREUR:  en-tête de page
invalide dans le bloc 6142 de la relation « articles_hs »
pg_dump: La commande était : COPY rma.articles_hs (arths_id, status,
no_art_bw, no_art_fourn, desc_fr, desc_de, price_public, rabais_art,
rabais_quant, rabais_fam, no_page, no_fourn, nb_stock, type_art,
nb_embal, unit_vente, arths_update, arths_price_v, arths_price_c,
arths_garmin_enabled, arths_rma_enabled) TO stdout;
pg_dumpall : échec de pg_dump sur la base de données « rma », quitte

I read a lot of formus, but never a clear solution, what could we do to
solve this problem ? (Except from taking the previous backups ?)

If we loose data it's not a problem, I just want to know how postgres
can clean himself again...

Thanks a lot for any advice...

Denis